Nice background but not the best conversion. It's pretty much flat gray with little difference in toning throughout. Why convert at all? It looks like it would be better in color (not knowing for certain, of course).
Yes, colour was fine, I wanted to try and get some depth in the clouds. Conversion was a little rushed, I lightened his body and face and then got pushed off the PPing PC. Will spend more time with it and post up another version of this image to compare tommoz.