I've never ordered personally from reefermadness. One thing I have heard people say is that a lot of their frags are "bag frags" - branches that broke off wild colonies in shipment. If that's the case, your success rate may be a bit lower than tank raised frags. Not saying there's anything wrong with what they're doing, it's just that shipping stress combined with acclimating to captivity tends to lead to higher losses, IME.
I did buy a frag pack once from another online vendor. The acros were all fresh cut and unmouted. Only one acro (out of 10) lasted more than 2 days. That kind of result soured me on the idea of shipped frag packs. After that, I started buying/trading locally, and I've had much better success.