There is a big difference between Bafang and the others, mainly if you ever need parts, you can get them for a BBS02 or BBSHD because they haven't changed anything in at least five years. My friend and I ride off road together, he on his Felt with a Bosch motor, then a Bulls with a Brose motor (he's been waiting a year to procure a new PAS module since the original one is faulty) while I've been riding my DIY bike which, while it's more powerful, is similarly more reliable. He's looking for a new bike and looks like he's learned his lesson since the first choice is one with a Bafang Ultra motor.