I just looked at it real quick, and a few things jumped out at me:
1) you can choose exercises based on what weak points you need to address
2) there are lifts included specifically for supporting muscle groups (ie rows and rear delt work for chest days)
3) there's more volume. volume helps build muscle, more muscle = more strength, especially over more reps
4) speed work
right now, I don't see any reason why that program wouldn't be good for you after you finish SS, but I think most people go to Madcow 5x5 or Texas method etc.
the most important thing would be for you to stick to it like you have with SS and eat eat eat.
just my 2 cents.