I did buy the UM MEXT as a "Like New" item from Andy not long after getting the Shuoer EJ07M HBB Kinda Lava edition, as the price was just so tempting and I had my eyes on it for a long time now. My order also had the new Liquid Links Conti that I got as an upgrade cable to the EJ07M, but I now use it with the MEXT.
The MEXT is a very worthy IEM, mostly as for me it does retain very high SQ with awesome clarity and definition while having that physicality in the bass department thanks to the Bone Conduction driver implementation (and let me say that I am not claiming to be an audiophile, but just an audio enthusiast that gradually got dragged into this rabbit hole of a hobby ;) , so please take my technical comments with that in mind). With that being said, I did get a little issue with my like new item, as I was experiencing a slight channel imbalance, as well as difference in the tightness of the 2-pin connections (one too tight to my liking, and the other one too loose). I therefore contacted Andy that directly agreed to get me a replacement free of charge (shipping back my item was also covered). So top-notch customer service here, thank you to Andy for both his responsiveness and level of support. But that does stop here, while my item was getting shipped back, MusicTeck put the MEXT to a lower price brand new as part of a sale, and I thus contacted Andy to ask if it would be possible to receive a "New" version for my replacement as the price was now the same as what I paid for my "Like New", and he agreed to it! I am very happy to say that my new MEXT is now working perfectly, and I am enjoying it a lot through my Cayin N3Pro and also xDSD Gryphon, rediscovering some of my well-known music with even higher levels of enjoyment. So I want to say a BIG thank you again to Andy, as I am very grateful to him for doing his utmost to take care of his customers with a level of support that is just unmatched.