Now I'm going to be honest and frank, because that's the way I am.
The first one is awesome. The shading is great and it really makes him pop out. Whatever you did right on that one, try to keep doing it.
The second one is decent. Some proportions are a little off and the shading is decent.
The third one is pretty bad, but entirely because the proportions are WAYYY off.
I'm not trying to cut down on you though, I rely on a grid for most of my drawings to get my proportions right. Some of my non-grid drawings have pretty bad proportions.