Looks good! Your weathering is nice and understated, it\'s really easy to go over the top with it (mostly because it\'s sooo much fun to do).
One thing I\'ve found works really well is to mask off your color demarkations with a bit of blue-tack. Roll it into sausages, you\'ll end up with an edge between your two camo colors that is more defined, but not as crisp as you would get from using masking tape. Silly Putty works for this too (no joke). One thing I\'ve found, with many years of using an airbrush, is freehanding edges takes a TON of practice (I do a lot of aircraft modeling as well). Hope this helps!
mike