One thing that Mannion had that Goff didn't have was a comfort level with the pro offense. He showed a firm grasp on where the receivers would be at what time, and this allowed him to put the ball there confidently. Additionally, he understands the protections and the nuances of a pro-scheme. That's what I saw whenever he was on the field.
I think in every other category, Goff has looked better. His throws are quicker, his quick feet are worlds ahead of the bricks Mannion lugs around (not trying to be mean, but watching Mannion try to move is a true study in inertia), his mobility in and out of the pocket is good if not excellent, his arm is better, and he has proven that he can get blitzed, hit, knocked around, and keep his eyes downfield, maneuver in the pocket and make the necessary throw. Mannion hasn't had the opportunity to prove that he can take the hits and keep focusing on the play, but its a rare enough trait, and Goff has it.
I like Mannion well enough, he seems like a good guy and a hard worker. But insisting that he is as talented as Goff feels delusional, at least to me, and from what I've seen of both guys. And that's all we can say, right? I believe that when Goff achieves a comfort level with a professional offense, with diagnosing the defense (was excited about our QB coach for this reason), and develops a natural feel for where his receivers will be, what they'll do, and where to put the ball, his talents will become a lot more obvious. It's learning for him. For Mannion, he would have to change his physical attributes and alter his DNA to develop the same gifts that Goff has. I know that sounds unfair, but all men are not created equal. Not when it comes to quarterbacking, certainly.
Short version: Mannion was experienced in a pro-offense. Goff was less so. Goff is gifted for the position. Mannion is less so. If there is a QB competition, I can't imagine Goff won't win.
