I'm not sold on Mallet. I don't like that whenever I see him on TV, he doesn't seem to complete many "tough" passes - by "tough", I mean passes that have to be fit into tight spaces, or timing passes. His release seems to be a bit slow, and he doesn't seem to have good pocket awareness. Lastly, he seems to be a bit of a whiner - aside from that, there are concerns about his character.
Maybe he'll ultimately be a franchise QB in NFL, but I'm not sure that I want the Bills spending a high 1st rounder on him.