I like this image and the dirty nails don't bother me in the least ;) I like the DOF, I think it's just right. I also like the conversion to the soft sepia. I think the dynamic color range of the hands themselves is right on the money except for the right side (see below).
The only two criticisms I have are that I think it's a bit hot on the right side which causes the eyes to move off to that part of the image. Not what you want. The other thing is it's a bit linear so not very compelling to look at for very long, at least for me. I wonder if a bit of a diagonal rotation might have added more interest and popped this over the edge into the 6's. Being REALLY nit-picky, there is something shiny in the lower left that I wish wasn't there. A ring maybe? Its just a bit of clutter with a beacon on it that calls for me to look at it.
I think this was a good choice for this challenge but it may have suffered score-wise because it's not a new look at the subject matter for people here. I didn't vote in this challenge but would have given this a six if I had.