It is harder to find a Piano 27 than a Piano 26 (of the kind pictured above). I just recently acquired a 27, though, and would like to make two observations. (1) Although the 27 is sometimes referred to as an alto and the 26 as a soprano, the 27 starts out only 6 keys lower than the 26. (2) I was surprised to discover that, for me at least, the Piano 27 is noticeably harder to play. The reason is that those lower six notes take quite a bit more air than is required by any keys of the Piano 26. So with the Piano 27, I’m much more conscious of having to adjust my breathing in the course of playing.
Although these Hohners are cheaply made, their unusual back plate is distinctive and, to my eye adds a quality look and feel. They and the Piano 32 have a distinctive, richer, more muted sound than other inexpensive melodicas, for example the Hohner Student (or Instructor) 32, which sounds tinny by comparison.