Our verdict
Pick the Purobot Ultra if you want face recognition, waste records and a box that seals and replaces its own bags. Pick the Litter-Robot 4 for its four-cat rating, standard drawer liners and established design.
The central trade-off
Automation. Ultra seals full bags and loads new ones using refill rings; Litter-Robot uses drawer liners you change by hand.
Health data. Ultra's rotating AI camera identifies each cat by face and records waste; Litter-Robot tracks weight and visits.
Size. Ultra is about 32 in wide; Litter-Robot is about 24 in square and 31 in tall.
Side by side
| Specification | PETKIT Purobot Ultra | Whisker Litter-Robot 4 |
|---|---|---|
| Cats (maker) | Not stated by the maker | 4 cats |
| Cat weight (maker) | Not stated by the maker | 3 lbs |
| Litter (maker) | clumping cat litters | clumping litter |
| Waste bin lasts (maker) | Not stated by the maker | Not stated by the maker |
| Noise (maker) | 35dB | Not stated by the maker |
| Dimensions | 20.86"L x 32.4"W x 24.01"H | 24"L x 24"W x 31"H |
| Weight | 46 pounds | 24 pounds |
| Warranty | 2 Year Warranty | WhiskerCare |
Values are the makers' published specifications. "Not stated" means the maker doesn't publish it.