Every free bass system is good in it's own way, but for a piano accordion player in the USA, quint makes sense to me. Titano are great accordions and there are lots of them - Virtuoso, Cosmopolitan, Royal, Emperor - at reasonable prices. In 120 bass form they are light and compact. I would love to see America re-discovering this aspect of it's own accordion heritage. Stradella bass in my opinion is very important as the foundation instrument, but it can be developed with ease by extending it to quint.
But there is nothing wrong in also looking further afield and stretching yourself too. If you are adventurous and want to explore the outer edges of the accordion (quite literally) you can play accordion with chromatic free bass. Take your time, do your research and you will discover your preferences with the accordion.
I asked Ludovic Beier why he plays Stradella (with slight mods) and he says he can play anything he wants on it and doesnt have the uncertainty of large jumps. And his playing certainly shows complete mastery.
If I were told I could only play Stradella, I really wouldn't have a problem with that. There are actually things you can do with Stradella by combining triads to form beautiful polychords that I envy. I think its biggest limitation is the fact that your voicings and inversions are inflexible. With free bass I have complete control over that, and for me, inversions are where its at.
You really don’t always want to be playing full chords with the left so Stradella’s inablity to produce sparse shells of just root/3 or root/7 is a limitation, particularly in groups, which is why you see a lot of players play RH only.
On both systems, the key to complexity of voicings, extensions, and alterations is the right hand.
For me, by using CBA-C on both sides I am more able to leverage the huge world of piano technique, including shell voicings, counterpoint, and additionally an overlap of notes that even pianists don’t have.
Its not just ‘free jazz’ that strays from vanilla ‘cycle of 5ths’ composition (Brazilian for example), and once you incorporate tritone substitutions, you’re again jumping all over the place with Stradella.