I have the amp research power side steps, and even after driving in 10 degree weather and through slush and ice, I've never had an issue of them not going down or coming back up. I did notice however, that amp only puts a meager spray of lithium grease on the gearset that actuates the steps. I placed a hefty wad of moly wheel bearing grease in there before installing the motors, so this may be keeping my system healthier than the installed-as-purchased ones. Also, I noticed that attention to detail during installation is critical as misaligning the step, causing thrust loads on the bearings seems to overwork the motors and its easier to accidentally do than you'd think. Prior to installing the motors, the steps should glide with no more force than the touch of a finger.
-Dan