I've been a user of Evernote for over 11 years. So long as I can export from the native app, and there are competitors that will import them (which Notion, Zoho, and OneNote do) I'm not too worried.
Evernote meets my needs well and every time I've looked at changing, nothing made it worth making the change. I want a place to take notes, stuff web clips and document, that I can tag and effectively search.
I would like to have some snappier options to taking quick notes as I still find myself opening Notepad to take get to writing out a note quickly. Evernote has never been responsive enough to fire up a note quick enough to take down a number on a phone call when I wasn't expecting to take notes. I can usually fish up a pen and something to write on or fire up Notepad more quickly.
My main issue is that Evernote have not yet lived up to its promise of being able to put all my notes and references in one place. I have to file many reference documents separate from Evernote because of file-size limitations, so I am managing documents in both Google Docs and Evernote and having to think about where I put which. I'm very disappointed that Google Drive integration doesn't work with Evernote Web.
If I do leave Evernote, it will be for Google Drive and Google Keep. If Google made it easier to import Evernote content I may have already tested this. If Evernote offered true integration with Google Drive, I wouldn't need to.
What I would most mist if I left Evernote would be the sublime web-clipper and the great, if not always snappy, iOS app.