This is by far my cats favourite litter box. Even our current feral house kitty will brave being in the same room as me to use this box rather than our other, traditional litter boxes. The high sides do their job to keep litter and the occasional higher spray IN the litter box, and the low but wide entrance lip seems to help keep litter in the box. The smooth plastic is VERY easy to keep clean, and litter does not clump and stick to the bottom.
The rounded shape means it does not fit in our litter box cabinet, but that is perhaps the only real issue I have had with it.