I had one briefly, on request imported it for a friend for his son.
Heard no complaints, but he was probably not a Cajun player.
I cannot tell if the 'standard' kings are similar as this was a modded one.
Apparently quite fairly priced too. IMO it was better than the Hohner Ariettes or other stuff like Weltmeister. A Castagnari C or D Max is quite expensive, very well made.
Alas not really suitable for Cajun playing due the slow push-up spring system used as is with most German one rows. But Irish box players like the Hohners and Castagnaris.
I have owned Cajun made accordeons and Hohners and other one row boxes.
The Castagnari has the lightest touch, fastest keyboard I have ever played. I have owned over 50 boxes and the Castagnari is the best built of the bunch and less expensive than the majority of Cajun made accordeons. Castagnaris are musical instruments compared to Cajun folk art.
Check the resale prices of Castagnari melodens compared to Cajun made a accordeons.. that will give you a clue.