Let me begin by dismissing the first entirely. 2010, as far as I see it, is an art style that you built off of. It hardly has any unique traits, and serves only as a seed from which the rest sprouted. Before I evaluate the ohers, I must say this; It would greatly benefit you to have at least five art styles. You've been experiemnting, and I believe that it does pay off in that the old, dark styles are suited for a specifric subject matter, just as the newer, puffier style is suited to cute animals. Instead of comparing one art style to the those of the past, evaluate EVERY style you have the ability to draw. Your work is Incredibly varied, and this is, in my opinion, your greatest strength. Unlike some folks whose art hardly ever changes, yours is evolving every month! Tis' a rare quality.
But thsi is somethign that you just decide... Do you want a final product? IS there a definite "best style"? Or is it like the sea, constantly shifting and bubbling up into something new?
It is up to you to decide this. I'm but a humble critic, HT.
I, personally, like your current artstyles over the old ones, save for a few. Take this how you will, and I'm poretty sure you already knew this,. but still. More food for thought.
Also, the stars at the right are my critique of your artstyle at the moment as a whole. :3 God's Blessings, Broski. May you ever continue to draw such amazing works.