I have an Omega Paw, if you've got the space they're great. Some people had issues, but if you carefully assemble the first time and make sure the clips are secure it works great. You roll it upside down, it sifts the unused litter into one compartment and then the clumps catch and get tossed into a scoop. You pull the scoop out, in the trash and done. I smack the bottom to make sure I get all the kitty litter clumps. It's like 30 seconds to clean the litter box. It's like half the cost of a Luuup and you don't end up with the litter-dirtied, peed on part sitting on the floor/ mat for the litter box, plus it has a lid so it helps with odor control. Way easier and you don't have to manuever the clumps into a bag, the scoop is like four inches wide, and has a handle. Just tilt it into the trash and take out your trash like normal. I love it, no mechanical parts/ motor to wear out on a self-cleaning robot one, no litter/ pee on the kitty litter mat, no scooping.