The first concertina, the one i started playing on, was a Marcus Music Concertina, borrowed from a friend. I then bought my first one, an old Wheatstone with wooden ends, which i still like very much. It has a beatiful sound, very warm. I played it for 6 years. Then Ralf Schlimm started building his Sevenmounts and since he does live near to where i live and we're good friends, i followed his work and played quite some Concertinas from him and it was obvious that they were (he was) improving fast. A year later I then told him, that when the right one came along i'd say yes and so it was. I can totally relate to the "feeling" thing you described. I had a good feel with all of his, from the very start, and i kind of "linked" with the one i now can call my own. The thing is, it's sound and feel together. And then there's good action, as a very big part of feel. And i was missing this one a little on my Wheatstone. It was very hard to play at higher speed on sessions. The Sevenmount does it pretty much on it's own, i think. (No, i don't get payed saying so! ? )
Hope that helps,
Doro