Wow so much effort it's also great that you actually post some progress images (more people should do that!) I have to say, I'm not an artist but a musician, but I prefer the 3rd progress image. Maybe because I just like it more "clean". That's just my point though :) I see the effort in color and shading but I prefer black+white on this one :) Do you use Illustrator for coloring or what software?
Best regards
Tom
PS: I also recommended you for NG artist.