We use it in our litter boxes. I, personally, love it, as I found some stuff in my YN that certainly didn't belong there and can't support the company on a personal level. You do have to like the scent of alfalfa, though.
If they nibble on it, it won't hurt them. Rats *can* eat alfalfa, they just don't get any thing from it and really don't like it much. Most rats will take a nibble and be done with thinking it's food.
Cool. I may have to try that. I switched from Care Fresh to fleece, because the Care Fresh made them sneeze so much. The fleece works well, but it has to be changed too often, so I was thinking about switching to aspen... but maybe I'll give the rabbit pellets a try.