Sorry if I haven't made a personal review, but this is my first tablet and I don't have a basis for comparison.
I was very busy in these days, and I haven't tested it very much.
For what I saw, the battery is quite good: after 9 hours of moderate use (some browsing, some music, root test, flashed a new firmware, wifi always on...) it's at 54%.
OS is really smooth... I haven't found any lag (but I used just a small number of apps).
Wifi not as good as my smartphone, but it works in all my house (20 meters and several walls from the router)
Build is ok: it's tiny and solid. Unfortunately I've found a couple of dead pixels, but they are really small and visible only on a perfect dark background.
The worst thing is that when I started it for the first time, the screen had a sort of "flickering". After some time, it disappeared. Sometimes it returns when I unlock the screen... but not all the times. Now I have flashed a new firmware (20130319 Cleaned) and for now it's ok...
For now, I'm happy (really good for the price).