That said, I have that exact model cordless, and I'm satisfied with it. I tend to use my corded one more, but the cordless one has done great on everything I've set it to. It cuts, grinds, poishes, and sands just fine. I've discovered that the cordless is especially effective for reshaping piano hammers. It does far better at that than the corded one does.
If you ever decide you'd like to invest in a second battery for it, as long as it's a Dremel 7.2v battery, it will work. There's two styles: the old square one, and this one. Both of them fit and remove just fine. Because that works, I have four batteries for mine.