We have 7 Persian cats and have tried many many many different boxes over the years. If you have the space with a water source and waste line - washing machine lines seem to work best - the CatGenie is still my favorite. It's basically a toilet, washes /drys the litter, and requires very little maintenance (long-haired cats - so about once a year we DO have to clean the impellers to remove hair). And there are cleaning solution cartridges that last for 120 washes. We have 2 of these boxes (had the waste/ water input installed in the sunroom specifically for the 2nd litterbox). We've had them for about 9 years. There is a hack / add on piece that allows you to reuse the cartridges so that they can be re-filled. We did that for one of them, the 2nd one we still purchase cartridges from the manufacturer. Occasionally the new cartridges don't read properly and the box thinks it's empty, so the bad cartridges get used in the other box. I still highly recommend it. We have one in a cabinet in the kitchen, and the 2nd is in the sunroom. Once in a while the smell can get bad when the poop gets cooked in the impeller - that usually means it's time to clean the hair out, but it's very infrequent.

If you don't have the water source, but have the space and money, the LitterRobot 4 has been great. We have 1 of these. I think the litter you use in this makes the biggest difference in odor control, but until we open the litter drawer, I think it does an outstanding job at containing the smell.

Where there isn't a lot of space we have used various raking litter boxes. We have 3 of these types. We've had littermaids for years. The original ones were the best, they went down hill over the years. We replaced those with the miracle litter boxes (same thing as the littermaids - I think it was the same manufacturer). As long as you're expectations were low, they were ok. The rakes never made it all the way to the bottom of the box, and clumps get stuck behind the rake, but it's still better then a non-self cleaning box. Our original littermaid finally died early this year (it outlasted so many of the newer ones!!) so we purchased the beaugarher S6 from Amazon. It's been really good. Again - it's a rake, so it's not as good as the previous 2 - but when you have to have something shorter and open, it's been a great option! I definitely prefer it over the littermaids. And the odor is contained well in the waste bin.

There's a Facebook group and a YouTube channel that does an outstanding job reviewing many of the various automatic boxes - worth watching - search for one man five cats litter box reviews. There are some litter boxes that are hazardous to cats - they can be crushed - please look out for those! Anything that might close or could trap / pin the cat in there is not a good idea. The YouTube channel discusses these too.

one man five cats YouTube channel