Some cheap winders only winds one way and only for a long time, not set timer.It would only rotate clockwise and then rotate for 60 minutes in one day and some non-stop. This is simply bad for the watch, it is suppose to generate energy from your natural motion, not by swinging your arms around for 30 minutes straight. That is why not all automatic watches, even those sports oriented ones, shouldn't be worn during sporting activities. Even some watches can get damage from the vibration of riding a motorcycle, that is how sensitive some of these mechanical movements are.
Wolf Designs, you can set it so it rotates clockwise or counter-clockwise or both and set it so it winds for how many turns every 2-3 hours or every 6 hours, etc... It's more ideal to have these options as watches also have different needs. Typical watch is probably suited for a winder that rotates clockwise and then counter-clockwise but others prefers one over the other. Not all watches needs the same amount of turns per day either, some has limits so you really have to be aware, especially if you spent $5k-$10k on your watch.
The speed or torque of the rotation matters, it can't be too fast or too slow or else it messes up the insides and the watch will require service much sooner than later. Cheaper winders also means cheaper motor and depending on the weight of the watch, some of them might not be able to handle the heavier ones. Plus cheaper motors also tend to fail and it slows down or spin too fast or just breaks.
Cheaper ones also usually have cheap fitting cheap cuffs (where you put the watch) and it doesn't fit properly so when it rotates the watch could fall off and if the winder has a cover, it could fall, hit the cover/wall, get stuck or continue to rotate and pretty much scratch the watch up as it spins. Cheap winders can also be loud, my Wolf Design is practically silent even when it rotates at night when I am sleeping, I do not hear it at all.
Some of these winders becomes a decoration too and the cheaper ones, well, look cheap. Fake wood or cheap plastic.
At the end, it is up to the buyer and I do not really want to scare people from trying it out but definitely be wary. There are also a lot of arguments out there about winders vs. no winders and it is up to you to decide which suits you best.