It's great for getting in the little edges like around the lip of rolls or up against the edge of list d'arrets. I used mine a few years ago before I finally went to a bench wheel and ultra-fine 6" wire wheel - BUT - the finish from that very closely matched the original munitions finish of my armor.
If you get the little cutting disks (
http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=420), I've found those to be fantastic for rivet removal. They also work for cutting steel, which is really helpful for something like a piece that has already been shaped that you can't use shears with. The wheels tend to get used fairly quickly, I think I used 50 or so in the last couple years, mostly just from replacing straps and buckles, although some was for swapping and not necessity.
Lots of uses for a Dremel on misc house projects, too. You should be quite pleased with it. Congrats on the acquisition!