Oh, wow, I can tell this shows a LOT of vectoring improvement from when you first started - the lines are really neat and smooth and I can tell a lot of work and effort went into this. I hope it gets accepted to the contest wallpaper gallery.
As for the wallpaper itself, I kind of wish you used more gradiented details and shading on those wings like you did on that green scarf(?) but the colors in general, are really nice. Just be more careful with gradients, especially the darker shades - they often leave those visible transitional lines (like on the guy's purple shirt) which sometimes look really awkward. Gradients are neat for shading lesser areas but on large-scale ones, unless done properly, usually leave those ugly lines.
Good job on this, overall and good luck in the contest! :)