Welcome!
I've purchased a Tao Tao Rhino from Superior Power Sports...with mixed reviews.
The quad got to me when promised, as was the paperwork, but there was no after sale service on a warranty issue.
That said, most of the Big Box Warehouses will probably leave you high and dry on this kind of stuff. Pay with a CC for backup.
I've found the Tao Tao quads to be ok. More "Old World China Bike" than probably some others but my Rhino hasn't given me any problems after I dialed it in.
Here are two places I keep in "my favorites" just to bounce through once in a while because they have a good California section. I'm sure others will come up with some more.
http://www.superiorpowersports.com/category_s/177.htm
http://www.powersportsmax.com/index.php/cPath/169
Just keep in mind that getting a good China bike/quad is all in the setup.
Good luck!