I've ordered from them once and the only problem I had was that the red brittle starfish I ordered expired shortly after delivery. I had Saturday delivery and was pleasantly surprised that I got a hold of customer service and was credited for the loss that same day. All other livestock I received (cleaner shrimp, 4 snails, yellow clown goby and royal gramma) all arrived healthy and active.
I have never ordered fish from them, but I have ordered starfish, crabs, and snails that I was very happy with.
I do not recommend ordering coral from them as the ones I have ordered were small and discolored when they arrived. I ordered a green acro that arrived Brown. I also ordered some yellow polyps that arrived nearly brown. I find that I can get better quality and better price (coral wise) locally.
I ordered a Swissguard Basslet from them a few months ago, and the packaging and service were awesome. They didn't have them in stock when I placed the order (even though they were on sale and I placed the order the day they were first featured on the site) but their customer service reps were very prompt in answering all my stupid and annoying questions (like "are they there yet").
I ordered a goby and shrimp from them with excellent results. The shrimp wasn't in stock at the first shipment so they sent it later with no extra shipping. Both arrived alive and stayed alive.