I bought a frame from AliExpress, but then I was looking to build a titanium mini velo, so didn't have a lot of other choices to acquire one here in the States. I used an outfit (Titan in Xi'an) that I had read a lot about, here on the forums and elsewhere, so was confident they were legit. A few thousand miles later, I'm very happy with my choice, but there's no question you're giving up most of your recourse if a problem develops down the road. If there's a problem upon receipt, however, I've mostly heard positive stories about resolving it, and had one myself regarding a wheelset I purchased.