On potential shown:
Mayfield A-
Allen B
Jackson B-
Rosen C-
Darnold C-
Mayfield has surprised me. I didn't particularly like him coming out, but I was very wrong. He has big time potential, and has every intangible you could want.
Allen and Jackson are run first guys, and will need lots of work and patience, but are such outstanding runners, they can be passable Pros with that alone. Allen has a Mahomes like rifle, and with lots of work can develop the passing side also. Will likely never be a super accurate guy, but with his overall abilities, he'll still be real good, and can be very similar to Cam Newton if he develops fully. That ain't bad. Jackson's arm is very good, if not elite, and with a lot of work, he'll also be a good overall QB for years.
Rosen has shown the clutch gene at times. He's been overall disappointing, but tough to judge without better coaching and a better team around him.
Darnold looks like he can be a competent NFL QB, with a mid range ceiling. You hope for more with the 2nd QB in the draft.