The only thing I would disagree with Mike on, is the bass. I actually think the S5 mk 2 is more accurate in the bass. It is also reaches much lower and has much more bass slam. If you are into some electronic / rock music which depends heavily on the bass lines, you may be better served by the S5 mk 2 (or jump straight to the M6).
If you really want to rock out, I would recommend the S7. The bass response is amazing, totally visceral in its impact.
Ken