Not the best…
"We used World’s Best when we were living overseas and continued when we relocated to HK. But I was always looking for a better alternative because not only did it track, but my biggest issue was that it didn’t clump well… Often it became a sludgy mess at the bottom of the litter box or worse. . . On occasion, a wet clump would stick to my cat’s bottom and he’d track it around the house when he’d sit somewhere. At one point I thought I was the problem (even though we clean out the litter box daily) but I’ve finally found a better litter, for less too!"