Im just giving you a general critique. If you are looking for something specific please post what it is your looking for.
I would have to go with the second. I like the detail that can be seen by the more closeup of the frets/hands. I also like how the back hand fades into black and you can't see the arm run off the page.
The first has to much black on the left side of the image and I dont care for the back arm running of the page and getting cropped right at the elbow. A tighter crop would help.
Also are the images supposed to have a slight tint to them? (green is showing through) If so then I think a True BW would do more for them.
im going to have to agree, i like the second the best, how the guitar and hands seem to grow from darkness. i think the top one is good as well, but i definately like the minimalisitc style of the bottom one which i think fits the subject matter better