A lot. Ely has done nothing but win since taking over for Plant. Even as a sophomore, playing backup to Aaron Murray (UGA now), Ely came off the bench in the playoffs and did something that Murray never did (beat Armwood, and in the playoffs). He led his team to the state title last season in his first year as starter. He just has that "it" factor at this level and other kids feed off it. He understands the game exceptionally well and is a real student of the game. Plant coach Robert Weiner sent Robert Marve to Miami (now at Purdue) and Murray to UGA. Ely is the most cerebral of the three. He doesn't make many mistakes and does a great job of scoring points and winning games. He throws an accurate ball and does a nice job of moving the ball around to various receivers. He's also nimble enough to avoid negative plays and turn them into positive ones. He's won a lot of games, has thrown a lot of passes, and has been ultra successful over the last year plus for Plant.
What may concern you:
He lacks ideal size at 6-1. Sure, Marve and Murray weren't any taller but the 6-1 quarterbacks still don't have the same upside as the 6-4+ kids. He'll never be that 6-4 kid. While he's very accurate and can make most of the throws, he doesn't have a rocket for an arm and his delivery needs some tweaking because he'll often wind up and throw. Some have called him a "system" quarterback and while I don't agree with that, the two previous Plant QB's are still waiting to make their mark at the college level.
Alabama came in and landed one of the state's best. He doesn't have the physical tools of a Jeff Driskel or Teddy Bridgewater but Ely has won more than both of those players and has been more successful at this level. Alabama has done a great job over the years with these types of quarterbacks, even going back to when they beat Miami in the 92 season with Jay Barker at quarterback. Florida's Big 3 didn't want Ely but Texas or Oklahoma didn't want Greg McElroy a few years ago. Nick Saban likes guys who are winners and who can manage games well. That's Phillip Ely to a tee. It seems like a great fit and he should be very successful in Bama's offense in the coming years.