I've put one on my deck and so far I love it!
The steam and ... buttons are raised more than the stock ones, so you can find them better (though there's no "Steam" text on the button, presumably for legal reasons).
Also on the stock deck I had the B button issue where it could get stuck sometimes, no such problem on the Extremerate one.
The fit is also very good, and it feels good in the hand.
I used to have the jsaux back, but I wasn't fond of the metal "heatsink" and the back didnt seem to mate to the front properly, so there was a slightly raised point I had to sand down, though I did prefer the jsaux raised back buttons.
Edit: I will add that having a good heat gun is recommended, and if I had to do it again, I may skip the trackpads, they were harder (for me) to do than the screen, I felt like I was gonna break them. AND the difference in looks is minor since there's a sticky black pad under them.