They are both made by the same company, and look and function the same… BUT there is a difference.

µTorrent has a much lower memory footprint than the program that Ludvig Strigeus developed it from, BitTorrent. Both still contain programming for adware (although in µTorrent this can be disabled).  Open-source clients that aren't monetized have even lower footprints. But like Popper says, I dont know if that makes them any "faster" so to speak.