I had to replace mine once. I think i know what is the likely cause of the reported failures. When the roll has ended the motor still tries to advance the fleece but obviously can't and just burns up after being over worked one time too many. The sensor that tells the controller the fleece isn't advancing is in the motor so it doesn't send a signal it isn't advancing until after the motor attempts to do so and it can not
It would be like chaining your car to a building once a month then mashing the accelerator and expecting the car to move. Eventually the transmission is going to fail as a result. To prevent this it's best to replace the fleece while there is still a little left so the motor isn't over worked.
I figured this out after the motor failed on my reefmat 500. One good thing is the motors are only about $25 and are easy to change. I love mine in spite of this flaw.
EDIT: Mine was installed 10/2022 and I replaced the motor once.