it's ok. some people like it, some dont. It's hard to see poop in b/c it's dark, and it doesnt hold moisture quite as well as some others but it's not a bad substrate at all. Personally, i like the dark color, but prefer cypress mulch over reptibark. I usually mix the 2 depending on what i have available
It does have the reputation for containing wood mites. (very tiny white bugs). Although they are generally harmless to your snake, you'll want to prevent getting them by freezing the bag of reptibark before using it. I've never had any problems after freezing.