Thanks for the replies!
Describing tone colors and why some are appealing and some not so much can be a challenge. To my ear the Pro-37 just sounds too far removed from the typical tones of accordions, concertinas, and harmonicas as they’re used in Irish trad to risk taking to a session. Any odd instrument is likely to raise eyebrows, but if it doesn’t sound too weird and if someone can actually play the tunes convincingly, they’ll be okay. I’ve read that piano accordionist Karen Tweed won an All-Ireland title in the “miscellaneous” category on the melodion, but I’ve no idea what kind–I’d be shocked if it was a Pro-37!
Besides the review here, one of the things that got me interested in the clavietta specifically was this recording of Troy playing the old jig Rakes of Kildare http://en.wikipedia.org/wiki/File:Melodica_rakesofkildare.ogg . To my ear, that’s very sweet, traditional playing with a great lilt and tastefully understated ornamentation. I’d guess there are plenty of Irish harmonica players who would be very happy with a performance like that. I’ll be interested to see how it goes with the clavietta. Troy, when you say the bounce is harder on the clavietta, are you referring to breath pulse or finger response? You get a great rhythmic pulse on the Rakes!