Full disclosure: as you may have guessed from my user name, I'm a Jets fan.
I didn't think much of Allen's college career but was impressed by what I saw from him last year. Obviously, his physical tools are unparalleled. But he needs to get his completion percentage into the high fifties, at the least, and get closer to a two to one TD to interception ratio. Even with the Bills' very good draft and off-season, the Bills are going to go as far as Allen takes them.
I like Darnold better, but if Allen plays well, the Bills will take over the AFC east over the next few years, due in large part to the Jets' mediocre front office and their poor drafts over the past several years. But if Darnold breaks out and Allen doesn't, things will swing the Jets' way in the division. It will be fun to watch.