I use this in my litter boxes and I like it. I do put a thin layer of finely shredded aspen under it. I found this way I use less and it comes out easier. It usually dumps out in one solid clump where they have went the most.
smoot, It does not swell considerably. It eventually all gets soft and sticks together in one clump like, well, clay. It gets like that from absorbing the urine over time. I have actually checked mine after one wee and it is still the same except it turns darker. Usually one corner of my litter boxes is very heavy from the absorption. It does get very 'thick'.
I have even from time to time if I am running low, scraped out the corner that is most used and continued to use the rest of it as it is generally not even wet.
Just yesterday I could really smell them and it has been less than a week with the cage cleaning. I changed the litter boxes and it was like a new cage again so it will smell after about 4 days but then so would anything else used it the pee in that spot constantly.