Porta SoftCat with Grass

I switched to this brand 4 months ago, and with 2 cats I've already gone through about 10 bags! I used Cat's Best before, and it lasted much longer. Somehow, this one gets used up really fast and it's EXPENSIVE! The litter clumps okay-ish, but there are always tiny bits that break off and stay behind. It sticks to the bottom of the litter box, and even though I clean it several times a day, there's a very strong smell of urine coming from a specific corner where it got stuck. It also spreads everywhere, even with a mat.