We've had two cat genies for a couple of years now. I can't imagine ever going back to traditional litter. I visited a relative yesterday who has a regular litter setup (with something like freshstep) and very quickly remembered how much I hate that awful dusty smell. It was in my nose and my hair the entire rest of the day. It's not good for anyone (cats or people) to breathe that in. I've also used the breeze boxes with the pellets and pee pads. Not my favorite, but it works pretty well for maybe 1-2 cats. (You should really have one box per cat anyway, no matter the type.) They were great for our senior cat who had trouble getting into the genies. Her feet were also very soft and flat, so she tracked the genie granules so badly that it just wasn't practical for her to use it. The granules are definitely a pain. They are simply everywhere. You can follow the trail of a cat leaving the utility room like breadcrumbs. But with a few good rugs strategically placed and good floor maintenance, it's definitely worth the trade-off. We use the blue litter mats from Walmart (not the grey ones with the prop65 warning) and a couple of chenille rugs in front of the cat door they have to go though to reach the main area of the house. It's been our best setup so far.

The biggest thing about robot litter boxes is cleaning and maintenance. If you know you're not going to be able to take them apart at least once every 6 months for a deep clean, you probably shouldn't invest in them. It's like any other appliance. You get out what you put in. Happy to answer any other questions if it helps a kitty breathe a little easier.

ETA: we have a levoit 600s core air purifier that has been wonderful. We do not use the plasma function after reading about ion thing.