I use Pine fresh clumping as well. The only problem I had with the other clumping brands, is when one of my foster cats decided to give birth in the litter...the babies of course were wet and got all clumped up. By the time I found her, I could safe all but one baby who was so clumped she sufficated...a terrible experience
But I also heard that the sandy stuff is so fine that the cats can inhale it and ofcourse it accumulates in their lungs which overtime can become dangerous.