You can read the quality of Grist itself in other reviews. However I'd like to point out how the team is making the effort so you can use Grist optimally.
1. YouTube videos
https://www.youtube.com/channel/UCx0ioQrrC-bIrkmZ7ZULr0g
These videos are based on "close to real-ish" use cases, not just "to do" simplistic stuff. Really useful.
2. Grist Community Forum
https://community.getgrist.com/top?period=monthly
(you don't have to be a current customer to access this)
You can see that either Dmitry (CEO), or Paul (CTO), or Anais (VP of Product), or Alex (Software Engineer), are quite responsive in helping users almost daily.
3. 1-on-1 Conference Call
This is not always given, but if you ask nicely they may agree. :)
So my wish, is that they keep on delivering good support like this going forward. I sincerely hope they will be even more successful.