Notion looks like a pretty interesting collaboration platform. It offers functionally like Trello, Evernote, and Google Sheets in a single unified product.
My biggest concern with Notion is data portability. I feel pretty safe that Atlassian and Google are going to be around for a while, and if they ever shut down products I use, there are so many users that there will be lots of good export tools. Even if Notion has a good API, it would take some work to extract everything and ingest into something else.
I’ve recently moved back to a folder structure of text files on Dropbox for my personal notes after using Apple Notes and Bear. It feels good knowing that my notes are essentially plain text files in a folder — no weird databases or opaque iCloud to worry about.