I like SF personally alittle bit better, I seem to get more of a running game going in it, both have there dynamic aspects to them though, in CAR the HB wheel play in gun-snugs undercenter, and the single back under center spread formation with the WR screen play &HB draw can give an opponent fits, the only thing I have struggled with CAR is when playing an experianced madden player and they see you are passing from undercenter a lot then the A-gap heat comes and comes consistent, with SF book I can adjust to A-gap heat better ....both good books I would prefer SF slightly over CAR due to being able to avoid A-gap heat better and being able to run the ball alittle better and still not lose anything in the pass game....just my 2 cents...