Perhaps their collection has improved, but as recently as a couple of years ago, they were on the very-hard-to-keep list. They didn't used to be (and were once considered an easy coral), but as their popularity increased, the collectors went to deeper and deeper waters to get them. Long story short, these deeper water specimens didn't do nearly as well as in the past, and last I heard, the situation hadn't changed much. This is partly due to collection, and partly due how they are stored on the boats before the collectors get them back to their holding tanks.
Anyway, they aren't seen all that much for sale anymore, and they often don't live very long. There might have been some changes, but do some internet research before you go get one.
Perhaps someone else can be a little more enlightening and knows more details than I do. That's just what we discovered after purchasing ours. (Which lived about a year and withered away slowly.)
Danielle