Directly from the U Fly Mike web site (news section):
09.03.09
QC-15: Bose just introduced a new QC-series, the QC-15. All versions of the UFlyMike, past and present, are fully compatible with either the QC-2 or the new QC-15.
I am currently using the UFM/QC15 set up for the first time on a trip and absolutely
love it. I did lots of internet research and talked to dozens of guys in the cockpit. It seemed almost unanimous that anyone that had used the UFM absolutely loved it. From my experience the UFM works flawlessly with the new QC15's. Which begs the question if Bose is so anti-UFM, why did they keep the same cord adapter on the headphone as the QC2's? There really aren't any accessories for the headphones besides the UFM and proprietary Bose "cellular adaptor" so why not change it? Bose is so anti-UFM as a matter of fact, that there is actually an entire page in the QC15 user manual titled "other considerations" which basically tries to talk you out of the UFM (although they don't mention it by name), and sell you on the X headset. Just doesn't make sense to me.
I traded my old worn QC3's in for the QC15's for $100 at the Bose store. I did a lot of comparison between the QC2's and QC3's during my initial purchase and found the sound cancellation to be superior on the QC3's. That being said, I can tell you that the 15's are much better than the 3's in both noise cancellation and tonal range of music.
My recommendation goes to the UFM for any headset purchase you may be considering. I can vouch for how well they work on the RJ!