I have a couple scoopfree boxes. It’s just a classic litter box shape with a rake that auto- scoops for you. Doesn’t do anything for pee. It works well for me/my cat. I bought the reusable tray, the disposable ones became really expensive over covid and they don’t handle heavy pee-loads well (plus wasteful). I buy the cheap crystal litter from Walmart, it works as well as their more expensive refills.

The scoopfree is open by default but you can buy a lid for it. My cats really disliked it when the litter box was enclosed so the lid is in my basement now. Does mean I have to vacuum around it occasionally. Smell isn’t bad unless urine builds up in the crystals because the poop is covered (but not “sealed”).

The poop capacity is finite and if you have cats that pee a lot you might have to change the litter more often. I have 2 boxes as I had two cats originally. I had to change it out between once a week and every other week. With 4 cats you’d ideally have more boxes and given cats will often just use the same one anyways, you might need to pull the tray out, dump and wipe it, then refill it up to twice a week.

There’s a configurable delay before the rake activates so it doesn’t scare the cat. There’s also a safety sensor so it doesn’t operate with a passenger.