It honestly switches every year. It’s hard to get a definitive answer because of the “my branch is better than your branch” naarishkeit that everyone goes through.
Years ago, when Rabbi Harris came to HQ from Brooklyn, one of the Brooklyn guys, who enjoyed bashing Wits and the other branches, began spreading the rumor that Rabbi Baruch Rauch would come from Milwaukee to bahelf the shiur.
Furthermore, even if you could ascertain which branch is more serious, it might not be the best branch for you. Different people have different emotional needs. Some branch roshei yeshiva are colder and more distant. Others are warmer. Some have a style which you may not like, eg the vast difference in styles between Rabbi Rauch and Rabbi Luban. With so many factors, only a rebbe who knows you well and knows the metzius on the ground can give you a definitive answer.