For me it's kind of like this
McCarthy: I think he's a career backup. He has a NFL quality arm. He can occasionally hit the big throw, but he's just so bland and boring the vast majority of the time.
Penix: He's got an arm and he's going to flash, but I think he's going he's going to be constantly up and down given his mechanics/decision making. The upside is really high though.
Maye: Highest upside in the draft as a pocket passer. He's got the arm, he can make all the throws, but because of that he makes a lot of throw he probably shouldn't. Decision making is his fatal flaw.
Williams: Highest overall upside. He can play as a pocket QB or create on his own while scrambling out of the pocket. The problem is he takes it too far and tries to do too much and in the NFL that's going to lead to a lot of turnovers.
Nix: I don't think there's a real high ceiling here, but I think he's a pretty safe pick, as far as QBs go, to be a roughly league average QB. He has a solid arm, and good decision making.
Beck: Super accurate, good with the reads, but the arm isn't NFL caliber. He's the kind of guy who carves out a decade long career as a backup.
Haven't seen enough of Sanders or Daniels to have an opinion.