If it took him 10 hours, it took him 10 hours. Really I don't see the problem. He stepped outside his comfort zone and worked hard on something. Sure, he's a glutton for punishment and brings this on himself. However that is not a critique nor a review.
That being said, I like the color choices. It's very pleasing. I don't care too much for the preset brush grass, but hey it could be worse. I do think more thought could have gone into the background but then again who am I to judge? I hate doing BGs. I really appreciate the small touches, like the trainer walking away in the background. Or the Ferrow? Hu-Oh? soaring through the clouds. This is a very strong piece for you. Proof you have talent. I just wish you weren't so stubborn. But your improving, slowly, but going. To me this seems like you were actually having fun drawing this, not obsessing over style. It's nice to see this side of your works. Keep it up.