Isn't NS an older emulsion which predates Fuji Pro S? I have lots of NS in 35mm, but unfortunately mine has lost a stop or so of speed. I find it to be grainier than Portra (but that could be because my batch has the speed loss). In my experience Portra 160 is more forgiving and produces beautiful, natural colors and in my experience thus far, with very fine grain. Portra 400 is very pushable - I got excellent results in a test in which I pushed it to 1600 recently.