I love this style of Portrait art. Especially when done by hand with pencil and paper. You can really see every little fine detail of the strokes and almost feel a texture about it. Not to mention this character is the best.
The detail in the face and the conveyance of the Vision you express is impeccable. Absolutely stunning the amount of detail you have in the face.
Your technique, along with the outside edges of the Portfolio, really shows a lot of depth. The only thing that's ever bugged me about this style, is sometimes leaving out bits of the clothes with just a floating head. However, you balance it out. Not diverting focus from the face, but still leaving more detail in less-detailed areas.
The use of space and orientation on the frame is fantastic. Perfectly framed, and gorgeous to look at.