That one looks sketchy. I don't see any brand name, so it's probably chinese.
The tiwanese make decent ones, most people I've seen on Kymco People scooters seem happy.
http://www.strmotorsports.com/showroom/scooters/people50/index.html
It looks like most of their 50cc ones are in your price range. They're good for around town, and i think you can get the bastards doing 40+ with minimal mods.
I really wouldn't trust anything out of china unless you can find a review on it. It's hard to find mechanics that will work on any of them, and new parts can be damn near impossible.
The 2year warrenty looks nice, but I dono what it covers..