I mean it could be an HA114,or a Regal, or even an Ariette, that is if you're playing by yourself,and if your tuning is dead on Cajun, but you would not go on stage with any one of those,would you?, that would not be authentic enough .
ultimately, seems like the title of that country gospel song hits the nail on the head: "The touch of the master's hand". Doesnt' matter how fine the instrument if you don't know how to make it sing; and it doesn't matter how low grade -- if you know what you doing you'll make it sing. Of course,if you combine a quality instrument with quality hands....
Do you really prefer your Bon Cajun to the Acadian? That really surprises me. I'm really partial to the keyboard and sound of my Acadian C box, though I understand that every box -- regardless of the builder -- has its own feel.
I don't want to gush too much over my own "brand", but I've always thought of Marc as a true innovator in the art of accordion-building. His boxes have a playability that I find unmatched elsewhere.
Granted, "feel" is very subjective, but I think that the reputation of Acadians as being the "standard" is very well deserved.
The quality of Quebecois boxes is also extremely high, particularly in terms of craftsmanship, but their keyboards have a very different feel (more of an Irish style).