I got an Advent one for Christmas last year, the price was something like £220, Windows XP, top spec (I've noticed the specs haven't changed at all in a year, mine is still "current")
Screen wise, I was told not to bother spending the extra for a larger screen, as the resolution doesn't change, so I got the 7" one. This may have changed since last year though.
Reliability wise, well straight out of the box it was a bit slow but chugged along. I followed some simple instructions found on Google for speeding up XP and now it really flies. Top tip, remove Internet Explorer, and use Safari/Opera for more stability and faster performance. The thing hasn't crashed once since I first got it, which is a surprise! Love it to bits. Don't expect to be able to do editing on it though, the screen resolution isn't good enough really (unless you can get better spec screen now of course)
One thing I really missed at first was the lack of optical drive, I couldn't find a reasonably priced usb one anywhere - I don't need a £100 DVD writer, just a decent portable CD Rom but apparently you can't buy these anymore!
