I really like Prococo thus far. Grow!t was really, really stringy, and not as nice to look at. It costs about the same as Reptichip for the most part - I haven't tried that one, though.

I've never had a feeder get substrate stuck on them. if you're worried about it you can put down a paper plate where you want to feed, but if they manage to ingest a little it'll be fine. They break down bones on a regular basis, and if your husbandry's correct they should pass the substrate without issue. Now, if they get an entire mouthful in a missed strike attempt, you'd probably want to help them out, but that's usually a bit more rare. I tend to feed while my BP's on her climbing structures, and don't usually have to deal with substrate as an issue.