The great thing about the Robot is that the litter doesn't have to clump hard for it to work. As long as the litter is small enough to fit through its screen, there shouldn't be a problem.
I had no odor until we got a starving kitten, who made it stinky, so I added a cup of Cedariffic litter to the mix and that worked like a charm. Cedariffic doesn't clump of itself, but it doesn't interfere with the clumping litter enough to keep it from working.
The Robot's rolling action not only take stress off the motor (most of the busted LitterMaids I hear of have burned out motors from trying to get a clump off the bottom of the pan... anyone who has given their biceps a workout the same way will know what I mean, it's like cement!) but it "breads" the clumps so that even if the cat doesn't cover, the Robot will do it for them.
My cat Puffy loves covering, and took exception to the Robot uncovering his clumps during the cleaning action, so at first he'd actually stand on the step (which stops it) to cover his stuff up, watch the Robot until it started again and uncovered it, stop it to cover, etc. In a week or so he figured out that it went away anyway, but that was a simple enough problem that fixed itself, and amused both us and Puffy.
I think most automatic litter boxes are dependent on the cat not hitting the wrong spot; one of the things that appealed to me about the Robot was that it offered relatively few ways for the cat to mess up, the but the edge problem is certainly one of them. If your cat or cats routinely has stuff on the edge of the box instead of in it, or dislikes hooded boxes, that's something to think about.
My James Bond is a big boy who likes to perch, but even he got seduced by the Robot's always-clean litter. He loves it now.
