If so, why? 
If not, why?
 
I'm curious. I think it's a massive waste of money with no real return. You can use that money to literally buy better hardware. I guess if you have top of the line hardware and need even more performance overclocking to the point where water cooling is necessary is logical, but to do it on anything other than top of the line hardware seems very futile. Change my mind.
 
 

I run a stand-alone corsair CPU water cooler and it runs much cooler than a high-end air cooler and it's relatively inexpensive.

I have the EVGA CLC 280 on an i7 7820X.  Temps on the new generation chips are higher because Intel used a thermal paste instead of solder based.  To keep the CPU cool (under 65C) it requires more than a heatsink and fan

I own Corsair Hydro H100i v2. I find AIO liquid coolers to be easier to install/remove compared to large air coolers. 
 
 
 
 
 
 
 

 
Moved to the Cooling section.

No I do not water cool my system. Its too expensive because I have to buy extra parts like blocks, fittings, tubes, pumps ect. I am too lazy to put it together and to do the maintenance cleaning when it comes time around.

Pros:
- Mostly silent
- Stable and low temps under load
 
Cons:
- Price
- Needs loads of work
 
Im doing watercooling because i think its more like hobby to me. While folding i need that extra cooling power (gpu temps are somewhere 42c while folding). Also i cannot even hear my computer while gaming/sleeping. With open headphones and computer nearby at table.

 
This is why I use the CLC 280.  Look at the ambient temps.  Unfortunately for the software, it doesn't read the CPU speed correctly...
 
 
***Found the reason for the invalid CPU speed.  When I run EVGA EleetX to set my RGB colors on my X299 FTW K...it sets the CPU at 4.2 GHZ (that is the speed set up in EleetX by default for some odd reason).  EleetX is in need of an overhaul.  Have to set the LED colors every day...since EVGA never put LED in the bios

I do it for low temps and noise level.  The "bling" is an added bonus.  I literally turn on my PC and it stays at that noise level no matter what I do.  No ramped up fans, etc.
 
For those willing to do it, its a hobby really.  If you're willing to pay and do lots of research, not plug and play, it's worth it.  The only maintenance is to drain and refill the fluid annual.  I only use clear premixed fluids.  Of course if the loop is deteriorating, flow, debris, etc. is when you'll need to do a complete tear down and clean out.

fearpoint
If so, why? 
If not, why?
 
I'm curious. I think it's a massive waste of money with no real return. You can use that money to literally buy better hardware. I guess if you have top of the line hardware and need even more performance overclocking to the point where water cooling is necessary is logical, but to do it on anything other than top of the line hardware seems very futile. Change my mind.

Air cooled vs water cooled -- both are constrained by ambient air temperature. It's just the efficiency that the heat can be dissipated into the ambient air. There are some pretty efficient air cooling solutions out there, so the argument could be made that water cooling is diminishing returns. Water cooling adds more failure points and complexity to a build. Personally, I believe there are more things that detract from using water cooling than it benefits. I was old-school water cooling back when Danger Den was still the answer. It's only gotten more expensive and flashy over time. Just strap a high-efficiency aftermarket air cooler on it and call it good. Spend what you save on a few SSDs.

No excuses for not water cooling in my opinion, unless you really like the way fans look or if you need some to fit in a super small case...

EK makes AIOs for 250 now.
Cools the cpu and gpu.
Honestly flushing a premade loop is not hard. Giant custom loops are a pain, but with enough chemicals in the water you can go awhile before you need to flush.

I water cool because If I pay thousands of dollars for a PC I want it to run at its ideal performance levels all the time, otherwise I may as well just get a XBOX ( nothing against XBOX).

It's funny I recently was debating this topic with my brother who is big on custom loops. It's been years since I've personally ran a custom loop, but I can probably speak for many on this, we did it primarily out of sheer enjoyment as a hobby, on top of the awesome benefits of a well done water cooled setup. However recent years my wife purchased me a AIO and I've ran it since with minimal issues. I also outfitted one of the other house computers with a Corsair H60 if I recall, and it's ran decent too, however I had some issues with it not making proper contact with CPU. I keep tossing up the idea of running a custom loop again, but after pricing out everything, it just turns me off. I'll also be honest in saying, I frequently leave my computers on for work reasons, and I'd far rather have a fan on a behemoth size cooler fail then the pump on an AIO or custom loop, as I trust a massive heatsink to cool my cpu then a small piece of copper with no water flow. But again both have their benefits, I feel as a top end air cooler wins in terms of piece of mind & reliability, however will be outmatched easily by any custom loop, and by most AIO coolers in terms of noise, cooling, and aesthetics.  

24x7 Folding power

Last 2 years and special last year I had really big desire to build watercooling, first with clear soft tubes to see how liquid behave in loop and than after first draining and cleaning maybe I will changing to acrylic tubes. 
 
I must say that I didn't used custom loop earlier because I want to build proper loop from separate parts.
Their price is only 50$ more than kits with less quality parts. You choose everything you want size and colors.
Obstacle for me was mostly budget. I can't say that I couldn't save money for watercooling, but constantly there is need for some more important stuff, new GPU, SSD 1TB, M.2, end such things. And than it's question to invest in cooling, improvement of my cooling or M.2 example. And than I never find some space to buy components from EKWB etc...
 
From other side there is a people who don't fall on every new upgrade and 10% improvements and invest in watercooling of little older platform. Z170, X99, etc...
But now I hope I will build loop because I found Monoblock RGB and some options for GPU waterblock compatible with few different GPU models... Next things would be radiator 280mm and compression fittings, few weeks later If everything is as I plan I will buy pump...
There is always options to save cost with some DDC pump, etc...
But I think D5 Revo 100 PWM Controll with Glass reservoir is great pump for small or big loop and I read they could work a long time. Only for people with tight budget as mine you never know for sure what is better, pump res combo or small revo D5 with top and small 80-100 reservoir separately. Because I need to think about components capable to use and in some smaller case, etc. When I buy something, that's it for 5 years, no changing anymore and they need to fit in any case.
 
Why I need and want watercoling. 30% because look cool and 70% because I could push CPU and GPU to silicon limit and temps will be acceptabla and fans will not scream. Everyone like temperatures in full load same as in idle and fans on 1400-1500RPM.