Absolutely top notch transparency and studio level performance. The best fit you can get without going custom. Excellent IEMs, thoroughly recommended!
My second "Like New" Hiby purchase form MusicTeck. In both cases, I received absolutely everything in truly like new condition, in fact I even received some courtesy add on items that are usually an extra charge. As for the R4 itself - a great device at a great price and system-wide PEQ really sets it ahed of peers in its price range.
To be honest, I thought this was going to be one of the dumbest purchases I've ever made. Turned out to be one of the best.
The Mest MK2 are incredibly musical and the soundstage and imaging are insane. I feel like I am in the room when listening to recordings. I have never experienced music like this. It feels like I can picture exactly where in the room each musician is and their distance from the mic. Vocals are beautiful, bass is great, tone and timbre are great. Sounds feel natural and very resolving.
Historically, all I've really cared about is vocals (primarily female vocals) being forward, present, and beautiful. I was deciding between these and the monarch mk2's and ended up picking these (largely due to Dan's Audio Reviews sound demos comparing the two.
Music that I have been listening to for years finally feels like its come alive and going back to other headphones/IEMs makes them feel so flat in comparison. I used to not care much for soundstage, but it is now at the top of my list of priorities. Vocals are maybe 5-10% too recessed for what I 'normally' look for, but that's fine; they sound absolutely beautiful. I turn the volume up 5-10% more than I would in other IEMs/headphones and they are immediately the best thing I've ever heard and I enjoy the slight increase in sound. They are leagues ahead of all my other gear.
IEMs/Headphones I own so you know how to weight my opinion: Moondrop stellaris (terrible), Fiio FH5 (bad), Mangird tea (great for vocals, bass bad), Mangird tea 2(good), Fatfreq Deuce (good for bass; vocals not ruined), Harmonicdyne Eris (mid with insane EQ), Beyerdynamic DT 990 pro (tamp down highs; pretty good vocals), Beyerdynamic Tygr 300R (mid; decent soundstage), HD600 (good but overhyped?), Focal Bathys (mid+ but can fatiguing, overall underwhelming), mest MK2 (best by far)
If the mest mk2 broke tomorrow, I would immediately order another pair and would not shop around to try something new.