Just got my stuff from GGG today.
Haven't installed yet, but here are my first impressions.
Buttons; The buttons are very white / slighly pearlescent in color. They don't look like white player 1/2 start buttons. They're cooler in color and less milky colored. They have a similar look to those white soap / shampoo bottles that are white and slightly hazy / pearly. The look like pretty much any other button otherwise, except for the tiny hole in the bottom that just barely accomodates an RGB led. I did notice that a
few of my buttons were a bit finicky about putting the button nut on. On a few of them, the positioning of the lead-in thread on the button was unfortunately located in such a way that the microswitch mounting bracket made it difficult to get the nut on. At first I thought they were screwed up completely, but it just turned out that I had to be a little careful about installing the nut. I wouldn't even mention it except that sometimes these things have to be installed in tight spaces, and I forsee some cursing during basic installation. They
look to have the same build as regular buttons, though, so this may be a problem with other buttons that I've been fortunate enough to have missed over the years. On a whole, they're just buttons and are of excellent quality.
RGB-drive LED boards;
The boards are very tiny. For some reason, I just didn't expect them to be this big. I mean... the picture shows them to be about 3 inches across

They're QUITE tiny as you can see in the picture. The perspective with the quarter is a
bit misleading... they're about the same length as a quarter. When you install them in the pushbuttons, they fit VERY snugly. Impressive really. I installed all of them with no problems. None were too tight, or too loose which says a lot for the execution of the build tolerances on both the RGB-drive and the buttons. Not that they need to be, but the RGB-drive boards are held in place by the microswitch. You will definitely not find frustration working with these in odd / dark spaces. They take almost no space beyond the button, so you should be able to install these anywhere that you can fit a microswitch. The boards can be installed in either direction... going WITH the microswitch or facing away from it. That doesn't seem like a big feature, but there are a few places on my machine where that will come in very handy.
One thing I would suggest is to definitely buy these prewired and resistored. It's not that cheap (2.xx extra each) but worth it as far as I'm concerned. The harness (as you can see) is absolutely solidly macine wired and perfect. You can see the 4 consumer wiring holes, labeled 1,2,3,4. They are VERY small. They look like they require 23 guage or smaller wire. Since I usually use 21 guage everywhere, I would have had to run out to The Shack to install myself. Anyway they're rock solid and I have no doubt that they will withstand more abuse than anything I could solder in. For you solder pros... you may not need them. I'm pretty decent with an iron, but those are just too small for me to feel comfortable with. One more bit of info... the preinstalled harness is about 2 feet long. If you have a frankenpanel... that might not be long enough to get where you need to go.
Anyway, I'm going to begin wiring up today. Screw it... I'm taking off work

I'm going to program a rough app today to set the behaviour of the led-wiz based on the game called. It's not going to be some amazing program, but I'll share it when I'm done. To begin with... it'll probably just check an ini file against the name of the game. I don't PWN @!! T3H R()MZ to I'm only going to be worried about it running less than a few hundred lines. If I get ambitious, it may check the mame .cfg file but I doubt I'll get that far. Anyway, I'll keep you posted.