sorry my experience is all in the UK, except I am in Australia for six months for work and I have seen instruments by three Australian makers at music festivals here. One was an Evans, a very basic concertina, another a Hooft which was very competent looking but was quiet and used colossal amounts of air, and the last one close or equal to a Suttner. The maker of the last one who I met at the festival asked me not to use his name as he didn't want publicity because he doesn't want the pressure of a waiting list. I would like to try a Carroll and a Kensington. My experience is that there is much more variation in the real reeded concertinas compared with the accordion reeded types which seem very similar to play but with slightly different build methods, quality and weights. Sadly it is impossible to get a real appreciation for a maker without owning one of their concertinas. There is no reporting of accurate impressions of concertinas, and no reviews like you would get for a guitar. The community is too small and the concertinas cost too much. When experienced people buy a concertina that does not measure up they don't say this, they sell it on to recoup their money. Almost any bespoke concertina will be better than the Lachhenal people often start with so many of the less experienced don't realise the new one is not quite perfect. Another complication is that a quick play on a concertina only tells you how it is different for th e one you usually play, and this can comeout as dislikes. If the buttons are in slightly differently spaced for eaxample, people will say it is hard to play, or if the spring pressure is different. More important is response volume and tone. Tone is so hard to describe people use like/don't like rather than qualitative terms.
My wife wrote to me (hullo darling) after seeing my post telling me I have tried another Dickenson, one that belongs to the wife of an old friend who we don't see much of anymore. It is a long time since I saw it but as I now recall it was an excellent concertna that I coveted at the time, always a good sign.