Thanks for your contribution
@Layman1!
Here's an update from my ongoing experience...
I've been listening to M2s for a bit now and am really enjoying it. I do think the sound is a bit on the warm side but it doesn't lack clarity (not dark). More of a fun, musical sound. Very enjoyable!
I'm also glad it isn't drastically affecting sound of hybrid and multi-BA IEM I've tried it with. Very subtle decrease in bass quantity (like 1-2dB drop from measurements).
I've only had one example of poor synergy so far, and that was with Heavenly Sounds Cadenza earbuds. They were overly warm and lacked clarity. Other than that, I've been pleased with earbud and IEM pairings I've tried.
The physical user experience is holding up pretty well so far. My one-handed operation video shows how easy it is to use the M2s. My only gripe the is that just like smartphones the glass back is slippery, so the case is a must. The case is nice but the cutouts on the left side could be a bit larger. If there was more space around the buttons, it would make the FFWD/REW buttons easier to use.
Shanling has my favorite Hiby-based GUI to date, and I've used many (Srsly!). It's very intuitive in my opinion. I was just chatting with the guy who designed it last night. He also helps conceptualize physical design for the DAPs. Cool guy!
I think that's it for now. Feel free to ask for clarifications as needed