Just another answer to throw into the grab bag!
I do my corals the same as my fish: float closed bag in water for 5-10 minutes to equalize temperature, then drip acclimate in a small plastic tub for 30-45 minutes... perhaps 60 minutes, depending on the salinity of the water in the bag to start with. I will tend to rush corals I get at a LFS
more than ones that have come mail order. With mail order, I figure the thing has been in the bag probably 18 hours already... what's another hour?
I don't quarantine my corals because while I know I should, my QT doesn't have adequate lighting and I don't want to stress the coral any more than it needs to be. No dips, just a gentle "swish" in the acclimation water before putting it in my main tank to get any debris, mucous, etc off.
Oh... overnight shipping, always.
[Edit: Also... to answer your question, "no" I've never had a coral die in transit. I would seriously doubt anyone has. They're not like fish. Death for a coral is often a long process. Any damage the coral receives during transit will probably not become apparent for many weeks. All my coral deaths have been due to clumsy snails/crabs, or incorrect placement by me and not correcting the problem in time. ]