I've heard mixed things about NE7M comfort, especially with stock tips. If you go in that route, you may want to invest in some other tips (hybrids?).
S4s are touted as being super comfy, which they are, but keep in mind that everyone's ears are different, and they could be less comfortable than what you were hoping for. Bass is not overpowering, imo, on the S4.
Try and look for it used in the FS forum. I can't compare the two, but you could do a lot worse, getting the S4s. [that's a compliment to them, btw]