I just bought that same bike from vbike.us I put it together this past weekend and I've got about 40 miles on it so far. Initial impressions are pretty good: Here's my observations so far:
1. power is what I would expect from a 250cc
2. it's geared pretty low
3. top speed is 60 mph (I'm 240lbs)
4. the tac shows a redline of 12.5k rpm...it's about wound out @ 6k rpm.
5. the shifter is WAY to short for a size 12 foot...I plan to extend it soon.
6. the brakes aren't the greatest, but adequate
7. the tires are super skinny
It was easy to put together and tune.
Here's a pic:
