I absolutely love the proportions of his face (spot on!) and the tattoo! Such a tough photo to draw - that angle's always hard and then you had the vast expanse of skin/muscle with little in the way of definition. Literally the only thing I can think is lacking is a bit of depth of shading throughout, just to add that really deep tone in.
But seriously, seriously good - thanks for sharing!!
No worries at all! I feel your pain about scanners The only think I can suggest is getting familiar with the 'levels' tool on photoshop - it gives you greater control over the contrast and brightness, and can often be used to replace the depth that you typically lose during scanning