I use Fresh Step and my cat, Peppie, has not complained about it yet.

Well you just hit one of my favorite subjects. If I could give away any of my senses it would be my sense of smell.
I can't stand any of the clay, paper, etc litters. The BEST is "Sweet Scoop". It is made from wheat and the enzymes eliminates any odors. It clumbs very well and has no chemicals. I am down to 3 cats from 5 and they all use the same litter pan. It's available for multiple cats. I use an old baby bathtub so it is large and deep. I keep a covered potty pot and scoop at least twice a day. The litter is flushable but with so many cats I perfer to toss it out. Hopes this helps.

I use Arm and Hammer and also sprinkle it with A&H baking soda. Have never noticed a litter box odor. I clean it everyday, too.

Fresh Step scoopable but I also empty both boxes twice a week and wash them out with Pine-Sol.