Calabim are definitely set up nicely. They have a good beeline, and strong leaders. Mansions make them a productive power house, and vampires later on gives them a way to conquer.
Both elves do well because, well, they are ELVES. Each has very strong game options, and need not worry about mining or bronze working.
Hippus have the most aggressive army in the game, and a world spell which lets them ACTUALLY conquer people, instead of just fighting a little bit here and there.
Belseraphs... I don't really know why they do so well per se. I think they use freaks fairly well, and for whatever reason, their AI just 'works'.