As a place where cats solve their major life problems, cat litter boxes need to be safe, comfortable and ventilated. For cat owners, we might want to consider if cat litter splash, wall stick to feces and if ventilation sand smell.
Personally, I think the size of the litter box matters the most, as if the box is too small, the cat would feces outside, or disliking the litter box and choose not to use it.
My recommendation is to choose larger sizes litter box. Whether they have an open-top or not, the shape, etc., the cat owners could choose whatever fits the best for them.
Lovely Cat Owner had bought what we recommended and found them useful