I like the 50mm/1.8 as a lens a lot. Just be aware that at 1.8 it can be soft. You can see that in this shot. Look at the knobs on the violin. DPC loves sharp, sharp, sharp. It also looks like you or the camera chose to focus on the far right and the ornamental hole (ya, ok, I don't know the parts of a violin by name). I would have focused on either those knobs I spoke of or the strings.
The bokeh is nice, but has a bit of an issue. The two straight lines don't add anything to the composition informationally so they just wind up distracting.
Bah...I was hoping to do a little better with this pic. I really like it. Oh well, photography is subjective, so it doesn't really matter. Thanks for the comments.