I haven't tried Coral Kingdom....but I'm a big fan of Reef Chicks! Great customer service, available for local pickup if prearranged, and cheap shipping for those who (like me) are a little too far to schlep down to their place. I've got a nice acan colony and a great looking red poci frag from her....and a few more that the old brain just isn't registering right now. In fact, I have a Reef Chicks order coming to my door today.
I've heard great things about pretty much everyone on this list, LOL. I'm looking forward to meeting Marke sometime in a couple weeks for a certain strawberry-flavored frag!!!