Isn't sani-chips the small aspen flakes? I've wanted to try them for my snakes but they are harder to find, and I read a lot of complaints that they are very light weight and maybe potentially messy in a dig box. I'm not sure I'd use them for mess reasons and that I don't like the idea of using absorbent or wood based bedding.
I did use alfalfa and it was ok - still got flung everywhere. The pellets are absorbent and could be a problem of ingested, but most dragons don't find them worth eating and they won't accidentally eat them. I used a 12x12 tray, some folks use small litter pans. If it gets wet it needs to be changed or it will mold, but the stuff is really cheep. I'd feed it to my roaches when I changed it out. I wanted to try millet but I couldn't find any locally.
Personally, now I use a sand/soil mix, but that is also messy and can make for a dirty dragon.