I had one for quite sometime, got it at a Petland when someone get a delivery from Flying Fish Express that was delivered 2 days late so Flying Fish Express told him to keep it free of charge. They're not as rare as some other fish, you can usually get one if you want, but they do carry a high price tag and basically aren't as nice as some of the other tangs, which go for a lot less.
They're pretty hardy, similar to Purple tangs, though they're not as aggressive as Purple or Yellow tangs. They do get some what large and usually don't look as nice when they're large.
As far as food they'll eat the same foods as other tangs will, so give then a lot of greens and it will do very well.