I use Fresh Step because it forms the best clumps and they don't break when scooping. Unfortunately it's very dusty and is perfumey like catnapper said. If I didn't have a "litterbox room" and had the litter boxes in the main part of the house I probably wouldn't use it because it's so dusty.

I used to use Tidy Cat for when I only had one cat and it was good because it wasn't as dusty but then when I added more cats I found it wasn't too good for multiple cats. The clumps would break easily so as more cats used the box the clumps ended up falling apart and in the bottom causing a mucky layer on the box. Not good - but if I still only had one cat I would probably use it.