have to diasagree, xenia are not the easiest. They are not super hardy and if they don't like the water, they just melt away. They also appreciate medium to bright light. Not really a starter coral.
(yeah, if they are happy, it's off to the races though.)
Same with Anthelia...
IMO, the most durable coral out there are large zooanthids like the Protopalythoas and then the small zooanthus, followed as mentioned by other softies like from the gorgonian families or mushrooms.
I still have a rock of them from my earliest reef, actually one of the only two things I still have from from my original reef
(the other thing is a solitary non-photosynthetic stony coral polyp that came on a piece of LR. can you believe a STONY CORAL has also survived 18 odd years of my abuse

)
They lived through several crashes, moves, tank changes, a poisoning incident and who knows what other horrible adventures.
They stayed closed for like a year after my first early horrible wipe which killed almost everything else, but they came back.