I have a Gray unit from Best Buy and a Champagne unit from Abt Electronics. The Gray has minor light bleed and a rattle near one of the dock connectors. Otherwise it works well. The Champagne has no issues other than wonky haptic feedback (works intermittently at best, otherwise just makes a quacking sound).
I'll probably keep the Champagne unit and just turn off haptic feedback (although it still tries to work even when turned off when adjusting items on the home page and when selecting images in the Gallery, at least). That is, unless Best Buy gets some units in-store that I can try out to see if I can get an absolutely perfect unit.
Otherwise, I love the Prime. The screen is simply outstanding--great colors, incredible viewing angles (I can watch video almost on the horizontal), and of course outstanding brightness. I can use it outside in the direct SoCal sun, which is exactly what I wanted. I did a quick video that kind of shows the difference (
ASUS Transformer Prime - Sunlight Visibility - YouTube) between the Prime and the Samsung Galaxy Tab 10.1 and original Transformer. I'm very impressed at how much better the Prime's screen is than the GT 10.1 in particular. Oh, and if anyone can explain the sync thing on the Prime, please chime in--it's weird, but I do notice absolutely no issues whatsoever outside of this video.
Performance is stellar. Build quality is good (other than the wonky vibrator). Wifi is weaker than some of my other devices but still entirely usable everywhere I need it to be. GPS works, although I haven't tried it in my car yet. Battery life is excellent. Overall, it's a great tablet and still $100 less than the equivalent iPad 2. Once I have the dock, my original Transformer will be going on eBay.
I think that ASUS really need to clean up production and fix some component issues (even in the Gray unit where haptic feedback "works," it's so weak as to be pretty much useless). Once they get things ironed out, I think they have a winner.