Hey there,
I purchased these recently from MusicTeck after being a big fan of the Mason II (Japanese version) and Mason V3. The V3+, assuming you get the awesome Phanes cable, is an incredible IEM. It's a big, open and natural sound with an authoritative bass response for balanced armatures. I've had other flagships like the U18T and still own the Tia Fourte, but the Mason V3+ provides a more musically engaging sound and its focus really isn't on technicalities so much as enjoyable listening. My opinion of course. The Phanes cable is one of the nicest cables I've used and allows you to basically switch between a Leonidas II-type cable and a gold alloy-type cable, which is the first of its kind. I don't use the bass tuning ports and just leave them fully closed (which is a slightly boosted sub-bass).
It's hard to recommend anyone go out and blind-buy a $4,000 IEM though. I was comfortable with it because I loved the Mason II and Mason V3 and I am a huge sucker for high end cables. Have you heard any of the other Mason models? Have you heard other flagships where they were not your cup of tea? I honestly think the Mason V3+ tuning is very easy to love. I don't think anyone would complain about the bass or treble and I'm pretty confident that the overall sound is safe enough to be loved by the majorities. But it is up to you on whether or not that is worth the price. I'm biased because my son's name is Mason
Also the IEM itself is absolutely gorgeous and very unique. It's hard to get a photo of it, but I went out into the sunlight to try to demonstrate the cool effect the shells have. Never seen anything like it.
Edit: I see you're in Vallejo. If you ever make it out to the South Bay, let me know and I could let you have a listen. Assuming this Covid-19 thing doesn't get us all quarantined in the next few days/weeks.
Happy listening,
-Collin-