I love my Chevron Tang. He is currently 1 1/2 inch, and I have only had him for 6 months. He did have a little bit of trouble eating much of anything when I first bought him. After a week of having him, he took on to sprinula brine shrimp, and that's all he ate for quite awhile. He will now eat flakes, mysis, and sprinula. He has recently taken a liken to nori.
I agree with the previous poster that said they are excellent algae eaters. If I get lazy and don't wipe my glass down for a few days, there is always a few little oval circles all over my tank glass from him munching on algae. If you have an algae problem and you have a big enough tank, this is a great fish for you.
I haven't had any aggression issues, though he is one of the smallest fish in the tank at the moment. He does get a little crazy aggressive when it's dinner time, but all fish do that.
I expect mine to maintain it's beautiful orange coloration for at least two years from now, maybe more. I don't mind, though, because I do love the coloration of an adult chevy tang. It's part of the reason I got it.