I've been using v10 on mobile/web alongside Legacy on the desktop for a while (and I always had the v10 desktop as well), but I honestly just don't like the look of 10 and the cluttered dashboard so if I have to make a quick note on my phone I now use Apple Notes.
It's true that mixing v10 and Legacy leads to glitches but I was mainly able to live with weird changes to bulleted lists etc.
I'm a novelist and screenwriter and I use EN for keeping track of ideas, characters, plotting etc. Because I'm using it in a creative way, it's helpful for me if it doesn't change or do anything too distracting.
I find the v10 font too jaunty compared with Legacy and I feel stupid that I can't seem to find a way to change the display (surely I should be able to choose the font I do so much of my daily work in - am I missing where I can do this?) It's also highly annoying that I can only get EN to learn spellings when there are spelling suggestions, but not when there aren't. Although this is an improvement on last time I tried it, when you couldn't teach it spelling at all.
I basically feel like I bought a house that the previous owner can come and redecorate whenever they want, but I guess all tech is like this now.
For me, v10 just has the feel of a website rather than a sturdy desktop app. Having said all that I tried One Note again today and... Ugh. So I guess I'll be trying to stay with EN somehow... Thanks for all the very useful advice 🙂