I've found armypainter paint brushes can take a lot of use/abuse and still be good afterwards. If anything, invest in a brush cleaner (I have "The Masters (brand) Brush cleaner and preserver"). This will help out your brushes a lot and lengthen their life, no matter what brand you get.
I have The Masters Brush Cleaner, too, but it doesn't work on my brushes. I currently use some GW brand brushes and a few from MWG. It's fine on the MWG ones but not on my GW ones.
Can't spell HERESY without A-Z-O-K-A-Z-O-R