Here's a short update to continue on my initial impressions for the M3s. I let them burn all night, in my ears as I slept. They continue to be comfortable and will be no problem if you like to sleeps with IEMs in your ears. I travel a lot so this is important to me especially in aircraft on long haul flights. For me, I've got the best fit and sound using Comply T400s pushed all the way down the nozzle to where the base of the tip is up against the shell. The isolation is really fantastic and the comfort superb. Even more so, for those of you who sleep with IEMs, you'll know that with many of them, when the pressure of the pillow against the body of the earphone, the position of the nozzle can get moved and dull the sound. Not here, at least not in my ears.
As for the sound, they have definitely opened up. I've been A/B comparing them against my Xelentos all day. They have very similar sound signatures which would be V or at least U and in many ways are quite comparable. I've always been impressed by how much sound can come out of those little pieces of "Audio Jewellery" with just a single driver in them. They make great travel buddies because they are so small and sound so good with deep bass and good transition to mids and crystal clear highs - remarkable really. The M3s take everything I love about the Xelentos and just marginally take everything up a notch. The bass is ever so slightly deeper, ever so slightly more detailed and they are pitch black so everything just stands out; they are just beautifully clean. The highs also have very good extension, clarity, sparkle and and an airiness about them. I've read that the M3s have a deep V and no mids and that was a cause for concern after ordering them but I can't agree. Everything from the texture of acoustic guitars to the reverberation of congas is sitting well defined right in front or beside you as it was recorded. Vocals both male and female are presented beautifully, neither too forward or too recessed, they are just sitting right there projecting from the middle of the stage, unless its Robert Plant moaning from left to right as the mix pans him in. I've listened to just about every genre now and subtle vocals literally whisper as they should, and while they do it differently Diana Kralls lip smacks as she kisses the microphone are just as well presented as George Clinton and Bootsy Collins smacking their lips. Treble reaches nice and high without a hint of sibilance and I dont know if its brain burn or a change in the ABM but the high frequencies, whether its screaming saxophones or subtle cymbal strikes are crisp, clear, detailed quick.
As I write this I'm listening to Paolo Fresu and Omar Sosa's "Singuldu" Album. Its and absolutely sublime recording with so much going on and the M3s are picking up all the subtle details. I'm impressed with these M3s. I'll never sell my Xelentos simply because they are so fantastic. They fit easily in a pocket and sound so good with the supplied thin cable and they have never let me down but I gotta say; in overall sound quality I think the M3s nudge them out and they can be had new for the used price of the Xelentos.
Anyway I am a music lover, an aficionado of quality and I might even call myself an audiophile because of my love for incredible rich detailed sound and my commitment not counting cost in my pursuit of what I love. Having said that, I do love an outstanding value and I'd put the M3s in that category. I'm not a professional reviewer, just a guy who loves music and has an opinion. I hope this helps someone or maybe even a few someones and I also hope to see a full & proper review eventually pop up in this thread to either validate my impressions or complete tear them to shreds.. LOL