I'm learning to play the piano accordion at the moment, and have bought a couple of second hand instruments(24 bass and 120) to do the learning on. When I (eventually hopefully!) go public, I want to get a slightly better instrument.

I'd more or less decided on a 72 bass as a compromise between portability and range, then noticed that there are 80 bass models made.

What is the difference between the 72 and 80 - is it just an extra row or are the buttons somehow arranged differently - does the 80 have any advantage over the 72?

Advice sought here.