If you absolutely have to buy without actually playing the horn, I've found Yamaha horns to be extremely consistent, as most Japanese manufacturing lines are. I've played on 4 Yamaha 221s, 3 Yamaha 321s that have seen extensive use and abuse over 6 years of school service and they play great. I've also played one 842, two 642s (one of which I bought) and have found that any horn I've played multiple examples of feel just like the others. I'd like to be able to compare the Yamahas to other horns, but I've only had experience with one other brand (extensive) and that is Marshall Music's Accent line. Terrible horns that degrade quickly. If you do have to place an order, and can get them to ship it to you, Marshall's Music (Headquarters are in Lansing, MI) will beat any other retailer in price if you request them too by email.

-Sh0ty

EDIT: Yamaha also makes good marching instruments, not necessarily relevant to the OP, but it just helps show that Yamaha does put a great emphasis on QC.