I normally use a Selmer Super Session F mouthpiece on my alto, which is fairly open, so I struggle to get the low notes with a reed that isn't soft enough. Compared to the Fibracell reeds I've normally used, I'd say this was about a 3, and a little bit stiffer than I wanted. "MS" would imply about a 2.5, and the difference is important.
I can get good palm key notes with this reed. I don't really do altissimo, but I expect that would be fine too. The sound is good, but it would suit a mouthpiece with a smaller tip opening better.
These reeds are also a bit narrower than I'm used to. On some mouthpieces, that could be a problem. I guess it's wide enough for mine, but it does mean I had to line it up carefully.