I prefer the older one (on the right, right?) because the skin tone is brighter and more lively/interesting, the new one looks a bit dull and grey. The dithering on the old one is also less noticable.
I'd brighten second-darkest skin tone a tad, it's a bit too close to the next darkest and too far from the next lightest. Then maybe brighten the lightest color on the near cheek a bit, so you can use it to smooth out the places with the highlight color.
The hair isn't bad, but it could probably use some AA to smooth out those highlights, right now it looks rather messy. Perhaps one of the skin tones would be the right shade to smooth it out.
The lightest color on the far cheek looks a bit odd as it brings that cheek closer than the other one, maybe just hit the outline with the brighter color. The dithering of the highlight on the outstretched arm looks also kind of bad, the solid bits of highlight on the left of the picture look much better than the dithered ones on the right.
The area around the eyes could use some cleaning up--if you have a photo-ref I could do more specific crit.
You could also drop the darker outline on the nose, the highlight would serve to outline it just as well.
Might want to add a bit of shadowing under the lower lip, rather than a highlight.
I like the expression you captured, and the facial structure and proportions seem quite good.