I have had the pleasure of playing a couple different Castagnari accordions over the years. They were double and triple rows. I agree with you - they are the best by any measure.
I have owned 3 Castagnari one rows, C and D, my current one is a D.
The other Castagnaris were
2 Lilly
1 Mory
1 Tommy
2 Hascy
1 Cortina... very rare
3 Melodeon sometimes called the MAX
John Doucet builds a fine Cajun accordeon.
The Castagnaris are built to another standard. You need to have owned them and played them, and taken them apart to make any judgement about them... there is nothing like a Castagnari, nothing.
I have owned 54 acordeons,when I buy another, it will likely be a Castagnari.