I have a litter robot 3 (the version without the wifi connectivity), and it does work, but honestly, I'm not sure I'll get another (I have multiple litter boxes and just the one automatic one, as I initially planned to replace one at a time as I had the spare money). It saves some amount of effort, but not a whole ton, it seems to let more smells out into the room than a regular covered litterbox, one of my cats doesn't like it as much as the other boxes, and once or twice it's randomly gotten stuck upside down until I reset it.

Ive not tried any others, but from what I hear, they're probably about as good as you get with these. (Ive also heard that one should definitely not get one of the cheaper devices that can be found on Amazon under a lot of different throwaway brands, that has a vertically spinning drum instead of an angled one like the litter robot, because they apparently have a design flaw that can kill cats).