The thing I didn't like about cellsorb was one, the price (about 19.00 for a 40lb bag) and two, the smell. After a few days it smelled like soggy newspaper and poop even though it was dry. The wood pellets just suck out the moisture in the poop well enough that they don't smell bad, but the cellsorb doesn't really do that for me.
It's great for allergy sufferers, I originally bought it for my males, (one has just bad allergies) after I took him to the Vet she recommended it for him. It works great for that, but with a high volume of rats, I couldn't imagine paying 20 bucks every few weeks for a bag.
If cellsorb didnt cost so much and I had a separate rat room, I would use it just for the benefit of being less dusty.