I think his neck is a little too short. It seems that he stands underneath himself a bit on the front legs, thus his shoulder is straighter which will take away some smoothness. I'm not a fan of his underline at all, but he does seem a little chunky so that may be why.
I disagree with the long ear comment. I think it's a combination of bad photography (Sorry!) and the way his ear is cocked.
He's got a BEAUTIFUL face - nice distance between the eyes and nose, and with just enough flare. I don't like the extreme dishes you see one some Arabs.
Although his neck is short, it ties in nicely to his shoulder's and chest.
He's got a nice short back that Arabians should have, so if his croup is a little high, this could be due to age.
Beautiful tail set as well.
And I LOVE that face!
Overall, I think he's a lovely boy.
Congrats on your purchase, and many happy trails with him!