I have the Lippert electric jacks, and they're working ok now.
But when I first got them, water got in the motors and froze up.
Others had problems with water and corrosion causing the motor to die.
Since then I've started using lots of dielectric grease around the edge and inside of the rubber covers. That has helped.
Another issue is that when the trailer is close to the ground and the arms cannot extend very far, they don't have much strength. It's easy to bend them, at least it was for me. Since then I've strengthened them and no more problems there.
How to strengthen armsI do think the regular scissors jacks are a bit more stable. But these are really easy, especially with a remote controller for the motors. Even if you do it manually, there's only two screw gears to turn. And like Hunting Dog says, they do adjust well to uneven terrain.
Guess I'm just lazy, as I do like them. :)