I began with a Rochelle in April having never even held a concertina before. I tried to rent one to try it out through the Button Box but at that time none were available. So I bought one from Concertina Connection and loved it. I played it an hour or two or more every day and made good progress. In June I found a used Kensington and bought it. It is fantastic, and I can play way beyond anything I could do on the Rochelle. The bellows on the Rochelle are slow. BUT, it allowed me to test the waters, to see that I could not only play it but enjoy it, and to learn. I was fortunate to find and afford the Kensington, and I would never have bought it without having the Rochelle first.
So, if you are interested, I have a Rochelle in a soft case with 50 days of use on it (perhaps 100 hours). You can buy it for $275 (about $200 less than I paid with shipping) plus shipping from Maine at cost. Price includes a donation to this site. PM me if you are interested.