During the Onderon arc of Clone Wars, we are introduced to General Kalani, a Super Tactical Droid and the first of his kind. Since then we have been introduced to two more: an STD named Aut-O and an unnamed one over Carida. Are those two lesser than Kalani, as they do not have the rank of general. In other words, does Kalani have more sophisticated programming?
Currently, there doesn't seem to be any canon info to indicate that Kalani was more advanced.
It's possible that he was given a title of General to ensure that the Onderon powers that be not question his military authority - such "puffed up" rank giving is not unheard of in Earth military politics.
It may only be circumstantial evidence, but the fact that Kalani is the only known droid to have correctly assessed that the shutdown order given after Order 66 must have been a trick, seems to serve as evidence to suggest that he was the droid with most capable intelligence.