I've got one of the very early Disc Extremes. I love the way it fits me and it's accurate. I don't like that it's dirty. I haven't tried the lehigh conversion yet, but have tried different primers, teflon tape, and with or without the disc the breech/bolt area always ends up filthy. I'm okay with this to an extent, but then seeing people with various guns that can shoot 20 shots and it still looks virtually unfired, I get a little jealous. Not that I really mind cleaning, but specifically in and around the threads for the breech plug on the barrel is where I spend the most time cleaning.
At least for now I think I'm going to wait until May and hope at least one person will buy one and write a thorough review of it. Or that they will offer something different in May.