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Got 3 of them and are all holding up great.

My thoughts on the motherboard... 
I have only had mine for 6 months so I cant really speak to long term longevity, but at this point I have no reason to believe that there will be any issues. This motherboard is really designed for extreme overclocking (think LN2) and as such everything on it is done to the extreme, which is a good thing. I was very much impressed with its just overall "beafyness" compared to well pretty much everything else out there. Sure it does not have very robust fan controls, RGB, built-in WiFi, built-in bluetooth, and 8 RAM slots... And I DONT CARE honestly that is one of the biggest reasons why I purchased this motherboard and I hope that EVGA never changes this regarding the dark motherboards... It does however have everything that you actually need and nothing more which IMO makes it one of the most practical and elegant motherboards on the market. 
 
Looking at the big picture... 
Who wants to deal with ASUS technical support? When I was looking at building my new PC I had narrowed it down to either EVGA or ASUS for the motherboard and one of the reasons why I went with EVGA was due to the numerous horrible reviews regarding ASUS technical support. Dont get me wrong overall most people seem to be happy with ASUS products, but boy when they have issues and have to call technical support it goes downhill fast. EVGA's technical support is 2nd to none. Then one needs to take into account the VRM overheating issues that are rampant with most of the X299 motherboards on the market including the ASUS Rampage VI Extreme (ASUS may have corrected the issue since, but here is a link to GamersNexus talking about the issue https://www.gamersnexus.net/guides/3113-asus-rampage-vi-extreme-vrm-thermals). 

I'll admit I was surprised by how feature poor the board was, which if I'm honest, is probably part of why I posed the question here in the first place.

I'm building a showcase system, that I will also use as my daily driver.  I'm doing so because when I went around looking to see what was being done out there, I'd see headlines like "ULTIMATE" "EPIC" "$20,000 GAMING RIG"...  And honestly?  A couple of them were built competently, but none of them were very impressive - and almost all of them were gimmick manufacturer supplied assemblies.

This bugged me - can't say why.  So I decided to do an actual five figure build - screw multiple cards - I want distinction.  To that end I spec'd a reasonable system in light of the material and tooling costs the rest of the build would entail.  All of the hardware save a couple USB adapters and the CPU has already been obtained.

The hardware list:

Corsair 1000D, 9920X CPU, 2080 TI Founders Edition, X299 Dark, AX1600i PSU.  Also, an EVGA Nu Audio, and EVGA Hydro Copper block (primarily for it's alignment with the CPU location - loop routing - you understand.), Gigabyte Titan Ridge expansion, An Intel X540-T1 10GbE, and sundry other bits. 

So far, we're just talking about your typical HEDT.  It starts to get good when you throw all that out and realize the build is in the case system.  The whole thing is powered by Aquacomputer's Aquasuite.  This will provide a manufacturer agnostic, elegant, single point of interaction for all things system related.  Powered by an Aquaero 6 LT, 1x Farbwerk 360, 1x Hubby7, 6x Quadro's, and 6x Splitty4's - Aquasuite will control 24 Corsair LL120 fans, a EK Revo Dual D5 pump, all temp and flow sensors, and all lighting - Regardless of the maker - and it will do it all without having to be logged in to some brand's portal site, without stupid 'social' features, and without the glaring security vulnerabilities their low-priority software development often brings with them (looking at you ASUS...)  It will be simply designed and built with German aesthetics and precision, and it will be fully system independent once configured - the software won't even have to be installed in the OS!

But, where it starts to get interesting is the case modifications.

I think the Obsidian 1000D is a beautiful - stupidly realized case - dripping with wasted potential so I'm going to rebuild it, ground up.  The materials will all be real, structural, elements.  While there will be a fair amount of acrylic, there will also be Pyrex, high carbon steel, real carbon fiber, silver and gold (sparingly).  The case will be fully toolless in it's execution; once assembled, it can be fully disassembled in a modular fashion.  Meaning that panels and areas of access will be hidden but effortlessly accessible without the use of a single tool (magnets!).  It will be Perfectly minimalist and quietly complex at the same time and it will include a series of ridiculous quality-of-life features (that I haven't finished sketching out yet).

Now, I want to be clear, I'm not fantasizing: Most of the tooling and components have already arrived.  Nor am I attempting to brag or misrepresent what it is I'm creating.  What I am trying to do is redefine a segment of the industry that has become boring and tacky, and unimaginative.  I'm doing it because I can and I'm doing it because I have nothing but time.  What I'm not doing is quad SLI stupidity, or unicorn vomit aesthetics.  I'm also not doing absolute top of the line hardware because it can always be upgraded at a later time, and the cost savings between the 9920x and the 9980XE bought me a table saw and a 24" plotter instead.

Things like that.

So... The Dark is the board I've chosen to sit at the center of this exercise in avarice.  In the end I want the system to look, feel, and be controlled in an air of effortless sophistication.  Teenagers don't have the money, and kids don't have the experience or the skill to pull this kind of thing off.  I'm tired of techno-samurai designs being marketed to 40+ year old tech enthusiasts (like me), so I'm going to offer an alternative - if only the once.

I don't necessarily care if anything comes from it, but I will eventually be posting some form of build log on overclock, reddit, hardforums, or whatever... My wife thinks there should be some kind of Youtube video, but I'm not set up for that, and I've gotten fat - idk, maybe.  Right now I'm trying to learn Blender to build it all digitally to save on material costs - that's probably the hardest part so far.  If I end up sucking, there's always apps like Inkscape or Smartdraw that are easy enough.

Anyway, that's where I'm coming from, and that's how I'm looking to use the board.  It will be overclocked, but nothing extreme, I'm primarily attracted to it's build quality and the purity of it's engineering. An area of potential concern is that there's just nothing out there about it.  No one uses it, talks about it, makes accessories for it (monoblocks, etc...)  It just feels a bit like a forgotten board.  Maybe it's because people resent X299?  I don't know, but AMD burned me once before - I'll give them a couple generations to prove they're going to stick around before they get my money again.

So yeah... Words.

Your point is well received.  If I may, though...
 
The accessories are not simply something to be acquired, things like monoblocks can often present both form and function - or just individual choice over the configuration of ones hardware - they are also an indicator of the broader market support or perhaps user base for a particular brand or product.
 
And that was my point moreso than a complaint about simply wanting to buy more things; I'm set in that department, and conceptually quite fond of the Dark.  EVGA's offerings in general right now actually.
 
Second, I truly hope I didn't give a fanboy air to the whole German thing... I think there is a historic, popular conception regarding the design and engineering ideals that German products seem to embody.  More specifically, between looking at the current generations motherboard offerings and the UI decisions of their respective ecosystems - including Corsair - I think a glance at Aquasuite would show that's exactly what their coders seem to be aiming for; comparatively, it certainly resonates with me.
 
I'm definitely not aiming at a styled theme, but I am responding to the statement because I am going to try to offer a notable counterpoint to the god-awful aesthetic and material choices on offer - and accepted by - both the enthusiast market and hardware industry today.  It's important enough to me that I'm investing over $10,000 USD of my own money to do it. I think that generally people do for themselves what they previously see done.  I also think that, in general, we conflate 'gaming rigs' with high spec, high dollar, pieces of equipment when increasingly that standard means something very, very, different.  For example, certain MSI product lines use PLASTIC for their heatsinks!?  What is that about?
 
Someone, somewhere was sold on the idea that aggressive design and performance had to look like a transformers character.  Over time individual business units have made financial choices that degraded even that standard so much that we are beginning to see 'premium' offerings that don't enhance performance but rather actively degrade it, i.e. The initial x299 vrm debacle, various manufacturer incorporated M.2 heatspreaders, plastic vrm sinks, actually most board 'armor' in general.
 
I think if there were a few more 'hero builds' out there that celebrated not only the builders, but intelligent design, craftsmanship, etc... The effect would begin To work its way down to the consumer industry, via certain high-profile modders, and perhaps eventually to the interested end user.
 
So that's why I'm not placing a value judgement on the virtue of individual accessories, and I'm certainly trying to avoid any perception of fanboy-ness.  No one is sponsoring this build... It's just me, my tools, and my experience.
 
 

I cant wait to see what you end up building! I agree with most of your points regarding current aesthetics of PC builds, most of them are very tacky. I really struggled finding a PC case for my recent X299 build that would both look good and have the functionality that I needed... Ultimately I ended up having to sacrifice aesthetics to get the functionally that I needed.   

I bought my X299 two months ago and am still getting the full feel for it. Originally, I enclosed it in a Fractal Design Meshify S2. Damn, nice case for the price, but I moved it out and put the Meshify back in the box and in my closet.

One thing I really like about the X299 Dark is that it’s a big, thick no BS board. EVGA put money into basics and let the end user decide where they wanted to invest supplemental additions rather than giving you lots of shinny plastic, although it has some, and useless bells and whistles that you end up disabling only to put your own favorites in place. At the end of the day the X299 Dark is a basic motherboard with no frills that focused upon giving you high quality parts. Granted, I have been only using mine for two months, but I planned my build for over six months and as my wife says I successfully “over engineered” or mind F&$/( my build.

EVGA support is top notch and I struggle to think of anyone who does better with exception of the EVGA CLC Cooler. I bought this to use temporarily while I built my custom loop. The first one cooled well but fans sucked. The second one did not cool well at all, but was quiet. Lesson learned! Bought a Be Quiet Dark Rock Pro 4 until I finished my build.

This is my primary rig BTW,

As for my choice of case. Given the bare bones, but solidly built motherboard, I wanted something more industrial for the case and while there are a growing number of options, I decided upon the Primochill Wetbench. It’s simple yet scalable while industrial.

My build so far:
EVGA X299 Dark MB
EVGA 1660 TI (Thick Card) GPU
EVGA 1000 Titanium PSU
EVGA NU
Intel i9 Skylake CPU
GSkillz Trident 32 GB RAM
CableMod Meshify Pro Cables
WD Black 2TB x 2 M2
WD Black 6TB x 4 RAID
Intel M2 Wireless & Bluetooth 5
Aqua Computer D5 Next
Aqua Computer Aquis 450ml Reservoir
Primochill soft tube 3/8 (10mm) id 5/8 (16 mm) od
Watercool HEATKILLER® IV PRO HWLuxe
Aqua suite
Samsung QHD 144MHz 4K Monitors x 2
Samsung QHD 144MHz 4K Monitors (Setup as Amazon FireTV & PS4 Client)
Be Quiet Fans PWM x3
Radiator 45mm (I forget brand but all Copper)

My son bought these and I love the gift but not sure about the long term outlook.
Razer Black Widow Tournament 2 Keyboard
Razer Basilisk Mouse
Razer Camera

I was using the Be Quiet Dark Rock Pro 4 Air cooling until I finished my loop.

For sound, I utilize some of my guitar gear. I have the EVGA Nu going out into my Marshall 50 Twin Acoustic Amp for music and game play. I bounce it off the walls with careful placement and a 45 foot cathedral ceiling it sounds amazing. I then use Bluetooth and WiFi to connect to a Mesh of Amazon Echo Plus 2 Devices when I want to keep things low & quiet.

Bottom line, I am enjoying the product and the build process. I am a retired Marine, what else do I have to do but shoot at the range, play my guitars and this.