I tried Feline Pine as I liked the idea of a natural, no dust cat litter. However, after using it for about a month, I was not impressed and switched back to my old clumping clay litter.
The Feline Pine did have a nice odor compared to clay litters, and was mess free in the beginning. It is made of compresed pine shavings in a pellet form.
My cats did not have a problem using the litter, but it was after it was used that I notices the inefficiency of it. It did cover up odors of thew solid waste, and was easy to scoop those out of the litter pan, but the liquid waste caused the pine pellets to break back down into pine shavings (pine dust really - it was very fine).
This made it impossible to scoop out the liquid waste, and the pine dust was very easy for the cats to track out of the litter box as it stuck to their paws. I ended up having to replace all the litter in the pan twice a week as all the pine pellets were breaking down into dust, making any clean up of the litter box near impossible.
It is a great smalling product, and it is flushable which was nice, but unless you want to be replacing all litter in the pan several times a week, it is not very cost effective nor an efficient litter to use for your cats. I have found that a clumping clay litter is much easier to work with on a daily basis, and requires less frequent full litter changes.