I use a nh-d15, and I like it very much. However if I was to buy a new one I would get the almost as good NH-d15s. The off-set makes it easier to work around (get at the ram, fit the video card in slot 1). You can add a 2nd fan to the 15s (if you have room) and get the 1-2 degrees you gave up (compared to the 15). One plus on the 15 is the older fans seem to be harder to hear for me even though they have the same measured acoustics.