Old thread, but this kind of question is still useful for people searching around later. A lot of the names mentioned here were the go-to options back then, but the online coral market has changed a lot since 2013.
These days I’d still say local stores and reef clubs are hard to beat when you want to see the coral in person, but online shops are great when you’re hunting for specific pieces. One newer option I’d add to the list is Corals Depot. They’re worth checking out if you’re browsing for WYSIWYG corals, torches, hammers, zoas, gonis, or general reef livestock.
Either way, I’d treat every online order the same: check actual photos when possible, read the shipping/DOA policy, inspect and dip everything, and don’t buy just because the photo looks crazy under blues.