Frank, I play a 30 button concertina, a very small/cheep one row "hero" and a 140 button bass, piano accordion. The last one is the one I'm taking lessons on. Someday I hope to be worthy of the instrument.
It's a 5/4 , five sets of reeds on the piano side and four on the bass side. It has what's called a tuba bass. I think A is set to about 62 hz on that set. Then it also has picalo (sp?) reeds on the bass side. And some real bassy reeds on the piano side. So you can turn it "upside down" if you want. Hich chords and low melody. I'm just not that smart on it yet.
I have my heart set on a little Stagi (sp?) Lilly two row c/g button box. Lovely littl thing, very loud strong voice. But its over 11hundred bucks. So I have to save up for it. I like the concertina & small button box because they fit on my motorcycle. However the piano accordion is growing on me, because it is so versital, any key, any voice. It's like strapping a small pipe organ to your belly.