Well, I usually prefer a border of some sort on sigs, It just looks so more organised with a border..

The smudge tool was used well on his arm, and the blending between the white and black looks great. The text is a little hard to read, A little too small perhaps.

Also, the use of effect brushes/effect c4ds could have made this great even better. Effect brushes are brushes which go over the entire sig, except the boarder. See my avatar as an example for effect brushes. Also, I can't really tell whether the abstract effects were c4ds or brushes, but either way they are looking pretty good. I love the smudging around his hair, helps him blend into the background. Also, that render was a great choice.

Keep up the good work, looking forward to seeing more (;

i love this style you made it
8/10 epic work