I think i somehow prefered the vector just like it was... because you actually didn't change that many things (except the colors). I believe it'd have been better to make a whole new bg. The sweat you made is a bit too 'blue' and doesn't look very real either (but i guess it's hard to make 'real-looking' sweatdrops !).
Otherwise, as i said for the scan, it's really a nice image of koyuki :)