Gracie relies on gi style leverage. Gracie style uses a traditional guard. The submissions and style itself is no longer evolving. Guard, closed guars, and butterfly guard tend to be the emphasis.
Bravo style is as much about improv and flexability as the Gracies are about technique over size. Bravo uses a Rubber guard as a system of its own and a replacement concept to the full guard. A lot of flexible leg subs (omo/ gogoplatas/ invisible collar/ mission control) are used and the style is better shifted to the no gi sportative style.
Guerrilla JJ is something i'm not that schooled on but I hear it involves more street tactics and judo. The system itself isn't a pure grappling system either (from what I "know"
) lol I don't know much about Guerrilla style.
Cracie style is very technical and tight. Caracie competitiors only need one opening to end a fight simply because their instructors are higher calibur.
Gracie style has become so integrated that people can usually defend whatever is thrown their way and are tearing up people from closed guard. Also Butterfly guard isn't the most solid weapon as an alternate if the Full guard fails.
Bravo is very good against ground and pound due to the half butterfly half highguard mission control. There isn't much risk to throwing triangles and other subs as the rubber guard is more dificult to pass than full guard. Most of all, Bravo style isn't mainstream yet and skilled instructors aren't going to be in all the major cities the way cracie gyms are so people might not expect it.
Bravo style isn't as tight and unless trained at 10th planet or somewhere skilled, you won't have the versatility and skill to follow through with the style. A lot of people bail out of rubber guard.
The emphasis on half guard is not good for mma. People punch you in that sport.