There are supposedly 3 common species in the hobby that are all look very similar. Seems most of the time they are just labeled as Acanthurus Dussumieri, apparently the colorations on a Acanthurus Palani isn't as bold but similar. I'm not sure if they get comparable in size, but if they do you might as well go with whichever you find first.
I've been told that the dussumeri has a white scalpel while the other 2 closely looking ones have a black scalpel. Not sure on the resource on that either.
I've had one for almost a year. It's a very fast grower and very friendly to everyone in my tank. He's with a blue hippo tang, purple tang, powder blue tang, 2 yellow tangs, Atlantic blue tang, convict tang, flame angel, Xmas wrasse, yellow coris wrasse, orange back fairy wrasse, and a few other fish. He doesn't bother anyone not ever new comers. He eats like crazy anything I put in. It's been in a 150 for almost 11 months and is pretty much starting to out grow it. It will b moving to a 220 soon. Got it last November at about 2" and is now easily over 6".