Recruiting is all about relationships when you get right down to it with most players.
It's the SEC, so sure there are often incentives too, but ultimately it's all about coaches, because the incentives are typically similar at most places. Other factors play a role, like being close to home, how they feel at the school, how much that school has won recently, what the depth chart looks like, what style they play, all that, but in many cases it's mainly about which coach they feel the closest to, and by that I mean which assistant/recruiter they have the closest bond with.
Marcus Mayers, for instance, really seems to want to play for Tyrone Nix. I'd bet that if we fired Nix he would re-open his recruitment, and I am very confident that he will finish his career playing for another defense.
The kicker in all of this is that I'm pretty confident that any member of the 2011 signing class that signs with either Ole Miss or MSU will be having his senior day with a different staff. So ultimately players make a heavy part of their decision based on the thing that's most likely to change at some point during their tenure at school.
If you want to spend all 4 years of your tenure with one coach, your best bet these days is to sign with a school whose coach was just newly hired.
Here is your 2011 list of SEC coaches:
Florida - Muschamp
Tennessee - Dooley
Georgia - Richt
South Carolina - Spurrier
Kentucky - Phillips
Vanderbilt - likely Franklin
Alabama - Saban
LSU - Miles
Auburn - Chizik
Arkansas - Petrino
Ole Miss - Nutt
MSU - Mullen
Here is the 2006 list of SEC coaches:
Florida - Meyer
Tennessee - Fulmer
Georgia - Richt
South Carolina - Spurrier
Kentucky - Brooks
Vanderbilt - Johnson
Alabama - Shula
LSU - Miles
Auburn - Tuberville
Arkansas - Nutt
Ole Miss - Orgeron
MSU - Croom
The 2006 list is the group of people who recruited the 2007 signing class for most of the year and developed those relationships. Those from that class that redshirted will be going through their senior year this fall. At 9 of the 12 SEC schools, those seniors will be going through senior day with a different head coach. At 2 of those 9 schools, those seniors are going to be celebrating senior day with the 3rd head coach of their college career. That's just looking at the head coaches. If you look at the assistant staff, I'm sure the turnover is even more.
Yet, the coaching staff is one of the main reasons, if not the main reason, why most players choose their specific school.