We use it on baby colubrids and in our deli cups for shipping/shows. It Sucks up a lot of moister, which is good during shipping if a snake urinates it doesn't stay wet, but have never used it as a substrate. The Bells use it, and seem to have good luck with it.
As for buying it, I see that you are in N.H, we get ours ( Diamond soft) from cold bloods out of Kingston Mass. It is $15 for a 20-25 lb bag, a lot cheaper than buying the name brand. If you go to the Manchester show in April he will have some big bags there for sale, and we normally have smaller quantities available too.
Hope this helps.