I'd take Josh over Kyler or Lamar...guys like Lamar and Kyler are hot for 3 years or less, then someone puts a helmet on the knee, they tear the ACL and, even if they stick around, they are never the same.
Im especially concerned about Kyler's longevity with that height, and the fact the offenses these guys run almost demand the QB be a runner. That's not the same as Vick or Steve Young.
Josh has that pocket ability, the learning, and film study, the work ethic that will make him great. Plus Bills are running a pro system that has more universal application and ability to adjust to QBs.