I've been through a year of litters with Mikey. Sometime last summer, he became adverse to using the litter box more than once, meaning every night between 2-5 am, he would pee on my bed because the litter boxes (all three!) were already used by that time even though I scooped it every night.
The Breeze system saved my sanity because it meant he would pee in the litter box more than once. In addition to two Breeze Systems, I also have a litter box with feline pine and another one with Boxie Cat clay (although I just got rid of the clay because I think my non-diabetic, Henry, might be allergic to it).
Feline Pine is my favorite. I started using it with my previous two cats when one of them developed breathing issues from clay litter. It smells the best, it dries out their poop so you don't end up with smears or messes, it's easy to clean with no dust, and it can handle Mikey's copious amount of pee.
With the Breeze, they don't use it for #2 when they have other options, thankfully. It's smelly when that happens because they can't cover it. I keep a box of clorox wipes next to it to clean it, as well. For the pads, if you just remove the pad, the tray will collect free urine and it makes it
much easier to do ketone testing or get urine samples. In fact, if you don't change the pad fast enough, you can end up with quite a liquidy mess.
My least favorite is the clay. It starts to smell quickly, it's dusty and messy, it's super expensive, and it was no match for Mikey's volumes of pee. It definitely was his favorite, though. The Arm & Hammer seemed to be the least smelly clay and least dusty I tried and my favorite of the bunch. The Boxie Cat is 100% clay but Henry started developing a rash on his belly and I caught him eating it so I've removed it from the rotation for a while to rule it out.
ETA: I just read online that you can use the Feline Pine pellets instead of the Breeze pellets in the Breeze System so I'm going to try this out! It would solve all my problems at once.