It looks like EVGA changed the color scheme on the X299 DARK.  In the pics from Gamers Nexus at Computex it's pretty much all blacked out:
 

 
And on EVGA site it's now this:

 
I really liked the original design much better with more black.  What do you guys think?

So this FAN is frankly nice.
I will choose.
 
Because,
If I Do 3WAY-SLI w/ Sound Card,
Side-Panel Fan's (4.7 inch x4 ) Air does Not Hit.
 
Therefore Z77FTW are Good.
 
 

That motherboard looks so good in black.

In addition,

Consider that the second photo (from EVGA website) is a 3D render for the looks of it. You can see the color transition from the light at the fan shroud near the left edge of the MOBO.

This is not a difference in lighting.  What changed was the M.2 fan shroud and the IO shield.  If you look at the fan shroud, you can see they reversed the colors basically with the bulk of it now being grey instead of black.
 
Anyone know if the ELITE series will scale to other components aside from graphics cards?  Maybe we got a sneak peak of it!  Elite in black.  How cool would that be, pick a color any color!

Scarlet-Tech
It is angle of lighting.. direct light versus off angle lighting. Not to mention, one is a real product shown at a show.

I hope that's the case I guess we'll just have to wait for more pics.  It just looks weird to me how the fan shroud is black on the left side with a very weird separation to grey if that's supposed to be lighting.  Looks more like a design to me but we'll see.  So X299 Elite, is it a thing?

FscuderiaX
If you look at the fan shroud, you can see they reversed the colors basically with the bulk of it now being grey instead of black.
 

 
I agree.  I don't believe its because of lighting.  The materials obviously are changed.  The top Nexus shot looks to me like their proto-type MB and the bottom one is their final retail product.  The glossy black to me looks like it got changed to more of a metallic silver, possibly aluminum to help dissipate heat while they still kept a few glossy black spots to the left of it.

Second one looks like a mock up picture but really the lighting could make a big change in the original picture colors.  Also the angle of the first shot is not that great and things like shutter speed could make a big difference in how black or grey a motherboard shows up. I will probably read reviews and try to get better input on the exact color but for me I would like deep black and glossy as much as I would like the grayish black since it reminds me of Batman personally.

The motherboard has glossy blacked out sections. they photo shows a light transition as others have said. The motherboard that we have shown at Computex should look like this in person. (note that this is not an EVGA photo)