Hi Nicky,
Mono really suits this one, and I do like the contrasty shadows. Far more interesting than straight, flat lighting.
I also find the way that he's staring off to the side intriguing - I really want to know what he's looking at. I'm not a huge fan of cheesy stare straight down the lens poses, so this appeals to me.
The one thing that's sitting a bit awkwardly with me though is the crop. I feel like I want it to be either wider to include his elbows and all of his head or a bit tighter at the bottom so that it looks like more of a deliberate choice to crop those bits off. At the moment it's kind of sat in the middle between the two, if you know what I mean.
I'd be really interested to know why it's your favourite shot.