probably the easiest breed to train
they are on par with german shepards. easy.
they think abit different but once you understand their motivation, then they are extremely easy.
they are not like a malinois or a border collie, and they seem not to be as clear headed, but they learn very quick.
They are probably the smartest of the bully breed, but that depends on the bloodlines, as well.
The dogs from protection working lines is infinitely more trainable than the ones from "doing nothing" lines, for obvious reasons.
The REAL question is, "can you deal with the brains?" Smart dogs need to exercise their minds.