Not speaking from personal experience- but I have been diligently researching Chinx ATVs over the last month, and the consensus seems to be (from people with actual experience of several brands) that while the Jetmoto is good....Vbike is better. They say the Vbikes in the same size, have significantly more power, and that the difference in the suspension is like night and day. I see far less complaints about the Vbike also.
Parts for Vbike are redily available, and the guy Tim who sells them through Vbile.us stands behind them.
I'd go with a Vbike (In fact I have gone with one! My 250 should be arriving tomorrow).
While you may well be satisfied with a Jet- considering that the same class Vbike would be cheaper (free shipping, too!) and more powerful, with a better suspension, and seemingly of a little higher quality, you might want to look i9nto one:
http://www.vbike.us/index.php
They offer a very large selection of ATV, too- and you can call the importer/dealer(Tim) and ask him questions- very nice guy.