HvH is right about getting sable brushes, and there are quite a few out there in different price ranges. I own a couple of Winsor and Newton Series 7 brushes that I used for figure painting before I got into vehicles, and they are the best brushes I've ever used. The do carry quite a price tag though, but in my opinion they are worth it. As HvH said, the point is what's important in a brush; the brush I use the most is the W&N Series 7 #2, and it has a finer point than most 00 and 000 brushes I've seen, and holds a ton of paint. I think it's an excellent all-around brush because you can use it for painting relatively large surfaces, and fine details just as well. It wouldn't be good for painting the large flat areas of armor however, you'd be better off with a square cut brush for that kind of work.
The best piece of advice I can give is don't cheap out on brushes unless you plan on destroying them by using them for glues or drybrushing. If you're going to paint with them, get good quality sable brushes. It really does make a difference.
Hope this helps.
Aloha,
Justin
Sitting inside in Hawai'i...