I've tried a number of their hay tabs (and just placed an order for more joint and immune support). I'm not entirely convinced they're effective, but I am convinced they don't hurt and the buns think they're great just as a treat. I have yet to have a negative interaction with oxbow as a company. Their entire product line is great and their staff are always helpful. Tonight I literally wore an oxbow t shirt to the garage to check my oxbow product stash before placing my order with my school's rep (and yes, even if we didn't get a discount, I would still feed my rabbits oxbow).