Crystal and caramel malts are very slightly different but generally interchangeable. If you can ever find a store that sells more than one brand of them (good luck) then just chew up a couple of kernels each and figure out which one you'd rather brew with, as they won't taste exactly the same and you might like one better than the other. But beyond that... I guess personally I don't really care about the scientific process differences in making them. Taste is all that really matters. No?
Cheers.