Aftermarket window motors sometimes run at a different speed than the stock one. If it's faster, then it will have less torque, strength, and be easier to stop or lock up over time. They also often require a wiring adapter, or the drive gear doesn't line up well with the regulator gear. I prefer the OEM motors, they usually will last the life of the vehicle. The plastic gear drive parts inside are made to be the weak links, so they fail and the motor survives. Then you just need to replace those few plastic parts, such as the drive pucks, cleaned out and put back in, they usually work like new, for another 10-20 years.