quality
I've owned all of the above and all have been good motors. I will say that others have had two or more of those and could pick some they would say are bad motors.
Alot has to do with the way you break it in and how you take care of it from then on. you might have a bearing going bad and keep running it and then a ball comes out and you blame the quality of the motor.
Occasionally you need to clean the internals and inspect the inners and you just may find something before it cost you the whole motor.
So as far as quality all the motors are good but someone that doesn't take care of it will make a good motor look bad at some point of their possession of it.