They are! I love mine. There is nothing more fun than watching a feather duster's feathers slowly emerge from its tube until fully extended in all their glory. I should note, these guys are worms, not corals. (technically this thread should be in the invertibrate section). I had a tube worm come out of its tube once and it was the ugliest thing I have ever seen. When they are in their tubes with their feathers out however, they are wonderful.
As far as which species to get: You really have your choice. You can get them from as little as $15 and as much as $50-up. I suggest getting a cheap one first, becausem, if it is your first you will love it. Then, later you can shop for the fancier more expensive ones. I am not aware of any species of tube worm being more fragile than another. It all depends on what tickles your fancy.
Send some pictures if you get one!