The M10 internals may not be a disaster in a pinch, but if you have pretty much any external mics, you're going to get better results.
Nothing against the 4061s, but since you already have omnis (your CSBs), I'd strongly recommend picking up a pair of cardioids as an alternate. (Acidjack's recommendation of hitting up Sound Professionals for both cards and a battery box is an excellent one, though I haven't heard that particular set of mics.) That way you have options for two very different recording situations. That and a whole bunch of trial and error should go a long way toward helping you figure out if you're happy with the results you're getting, or want to go down the slippery slope of endless upgrades.