Back to the original question of the post..."A long shot here"...
I wonder who else is out there alive that actually had Mario as their teacher/instructor? Lots of nostalgia going on here in the thoughts of this thread. I was a kid 11 when I got a Stradella, 12 when I got a Cordovox, 13 switched to a C Style, parents met Mario through Chicago Conservatory of Music, got his accordion started taking weekly lessons (remember George S occasionally being there practicing/lessons ...remember conversations about George being Mario's hope to really introduce the Mochino system to the accordion world.)
Fell in love with the beauty and challenges of classical music (all the time being laughed at for playing the squeeze box from classmates) from Fur-de-Lis to Mozart's sonatas, Bach 2- and 3-part inventions, etc. The depth and capabilities of the FB system captivated me, competition inspired me to higher levels of mastery (ATG). at 15 (North American Champion-Bach's Italian Concerto -3 movements) then ATG nationals where top 2 go to the world (Jeff Lisenby 1st, Karen S 2nd _but she had already won the AAA (now NAA), and I place 3rd. Jeff was early 20s, Karen mid 20s. International championships that year the Russian (late 20s) got Glod, Jeff Silver, Karen- Bronze... but it was the conversation with Mario afterward that I remember...
He spoke of the things you mentioned above-the Russian player could make it sing (Mario was always trying to get me to the level of music not just mechanics ("Lots of folks can sign notes" he would say, "...but Sinatra"... ) He said the Russian, and Jeff and Karen could make it (music being played on their accordions) sing and in time I would be able to mature to that... and that's where he said he felt the drawbacks of the system kept the accordionist from Russia achieving even a higher level in the Bach piece. No doubt I needed to grow up -much of music has to do with feelings from life experience, growing up... not just technique. His personal challenge to me was to grow into making it sing and his delight was having the instrument that would not hinder that on the level we were headed.
I understand now what it meant for me to be the only competitor with Mario's instrument during those years. (ATG)..I'm competing, he's having the capabilities of his instrument on display-especially since there was no one in the competitions doing the difficulty in the left hand that we were doing and demonstrating. His dream-that his accordion would help bring the accordion to the American orchestra scene as it was in Europe-I think that dream had some hopes in me continuing.
It was still an era where the higher competition featured the flashy difficulty of the Piano/ soprano side of the accordion (like Jeff L playing "Paganini Ana" accordion version) and as we entered discussion of next season and me expressing the need to get a better balance of flashiness/difficulty than just the intricacies of what Bach offered, we started exploring Rachmaninoff Piano Concerto II and how this could be done (upper range on the Piano side was limited)...but I reminisce...
Folks from Kansas University recruiting me led to discussions (short) with my parents about my plans and what to do with accordion/music...was this just a hobby/High School thing? or did it go deeper into a pursuit? /Career?
Why do I tell you all that.... Original question.
This is what I know... much wonderful music, enjoyment, personal edification, challenge, sense of accomplishment can and is being accomplished through all the accordion systems. The accordion (any style) is a very sought-after item in the Nashville music studio scene.
But...
Should you ever want to go deeper, explore the higher echelons of classical composers (the type that features piano players in orchestras) then in my experience the Mochino FB will be a system that will not disappoint. Its ease of use and layout helped me go from "Beautiful Brown Eyes " on the Stradella, to considering Rachmaninoff in under 5 years and this as a high school kid...
Well, I hope your "long shot" has resonated with an unexpected trip down memory lane with me and maybe inspires you to take a chance...
Three things are needed to make it sing like Sinatra:
1. the simple mechanics of the instrument used
2. the technique/ skill honed to master said instrument (time and practice here)
3. musicianship -only comes from life experience, love, emotions and conveying that through the notes played
The discussion has taken a left turn here from what was intended...kind of like the question of "which is the best bible translation?" Correct answer: the one you will read and follow.
The best piece of equipment, like the most nutrious meal, if not used or followed does not benefit anyone.