Still a work in progress, but I'm at a point now where progress is slow going and would definitely appreciate some fresh critique.
A couple areas I'm having particular trouble with are the transition from the deltoid to the upper torso, as well as the flow of the trapezius from the back of the skull to the clavicle. If anyone has advice on those areas or anything else, feel free to comment.
I'd say that one problem is that all of your muscle transitions are a bit too smooth. Check out some Bridgman to give you some ideas of how to go about simplifying muscle groups into distinct segments.