I have 2 of the self cleaning litter boxes. I found them to be $20 less at Petsmart, Petco is so expensive. I also purchased the tent so it gives the kitties a bit of privacy. I have 3 kitties btw. My husband loves the thing since he doesn't have to clean the litter box as much. He just disposes the dispensors and it's done. The dispensors come 12 in a box, if I'm not mistaken. So, what my husband does to save some $$, he dumps out the stuff that's in the dispensor on trash day and he puts back the dispensor that way he doesn't have to put a new despensor in. He will replace the despensor after a month's worth of use. We purchase the tent in Target sometimes Walmart may have them as well.
Some drawbacks are: it tends to get stuck if there's a lot of material in the box also, you have to make sure the comb in the back stays clear of material. I would suggest the clumping litter the more it clumps the better. We use the arm & hammer.
I give it 2 thumbs up! I would suggest in getting the biggest one since that one has a stronger motor and is wider, deeper and it tends to get less stuck. I know they are a bit pricey but for me they are so worth it!! Good luck!