In my lifetime he is the top Alabama QB. It's very hard to compare him to Stabler, Namath, or Starr, because those are all Super Bowl quarterbacks.
Unfortunately, the Alabama quarterbacks of my lifetime are career NFL backups, if that. AJ has a chance to break through that though, if he has a great season he could land someplace that wants him as their starter and might be willing to use a first round pick (another thing I don't believe has happened in my lifetime).
As it is right now, I used to feel Jay Barker was the ideal QB simply because he never did anything to lose a game. He was a winner, he didn't make mistakes, and even if he wasn't the most talented, he was a champion. I also was a Phillip Sims fan. I still am a Phillip Sims fan, he has a lot of talent, and he's in a bad situation now, but he could still turn out to be an NFL player. I didn't believe in AJ, not because I questioned his talent, but because I questioned his decision making. Clearly, I was wrong. He has reached the level that it's hard to imagine I'd want anyone else playing QB for Alabama during a championship game.