I think a couple of minor things would make this shot really pop. 1) The part of the strap you see just above the guitar almost in front of his face. 2) a hairlight will separate the background and his hair, I find it very distracting when the hair and the backdrop are blending like that. 3) this one is just kind of a personal opinion, but I think if you are going to cut things off, crop it tighter. I look straight to the cut off elbow.
I like the whole idea, other than the lack of the hairlight, the lighting is good. Pose is good.