Just got mine this evening, and so far I like it. As mentioned, it is very responsive. Whatever Google did as part of their "Project Butter" claim, it seems to work quite well. The Chrome browser still has some rendering issues on some sites (different-sized text in different areas of the screen), but at least they brought back the "Request Desktop Site" option.
Although I've seen the reviews of it, I was still somewhat surprised by the fact it's pretty much the same layout as ICS on the Galaxy Nexus, vs the other Android tablets I've seen (menu keys in the middle instead of on the bottom left or right, for instance). It still does seem to work fairly well, and since I've used a Galaxy Nexus before I don't really have any complaints from the user interface side.
From what I can tell my unit is fine from a hardware standpoint as well. No dead pixels, no noticeable issues with the screen lifting up, no flickering. Hopefully it stays like that.