The base is about 7 3/4" in diameter.
I've had mine for a few months and it's been pretty good. I haven't noticed any pixel defects on mine fortunately and the response time is generally fine for games IMO, though some exhibit a little more ghosting than I'd like while others are quite good for some reason.
There are a couple strange things about it that I have noticed:
1. The top area of the screen seems a bit darker than the bottom; something that is not highly-noticable until you look at a solid-color screen. I looked at some other brands at the store and noticed similar characteristics so I'm assuming it's normal.
2. The auto-adjust feature is great and I find myself longing for it when I use a new resolution/refresh setting on my CRT and have to adjust the size and geometry manually to get a good picture. However I find that, at least with my setup, dark text ends up with a white highlight on the right edge the way the monitor configures things so for the setup used for my Windows display I found I can manually tweak the fine adjustment to mostly eliminate this without sacrificing image quality. Clear-type helps here too.
This is my first LCD monitor so I don't have much experience with others to compare to but overall I'm happy with it.