Oh, that is awesome. I sent UM a message that I'd like to begin the process and getting any info I need before I book an appointment for impressions.
I'm loving the MEST Mk2 so much that I told my wife this makes it my endgame. She groaned and said that it must be my sixth or seventh endgame now but I really mean it this time. The tuning of the Mk2 is exactly what I would describe if someone were to ask me what my perfect sound would be. Musical bass with just enough punch to be physical without being overpowering, smooth mids that give vocals a "singing to you" quality instead of just existing in the mix, highs that bite and give an aggressive edge when called for (guitar solos can sound other worldly) without being fatiguing.
The Soundstage is hands down the best I've heard from an IEM and on par with the best of the open-backs (the width of the SS wows me more than my HD800S did). Cymbals and HiHats are also the best I've ever heard from an IEM, that's always been the tricky part I found. DD's aren't adept enough at the high range to give the tizz that a closed HiHat needs and BAs alone have a weird tone for HHs. The BA/ES mix for the frequency range that covers HHs is perfect, get the hit sound from the BA but the reverberation and air from the ES.
Admittedly, I haven't heard any higher end units as my $1000+ experience with IEMs ends with these and the Andromeda S. I'm currently signed up for the Canadian tours for the EXT and Phonix, as well as the three new Fir Audio models but I'm considering dropping out. If I never hear them I can pretend that I'd like the Mk2 better than them anyway but on the other hand, if I stay in and get them and don't find them compelling over the Mk2 it's better for the "grass is greener" syndrome in the long run.