I switched to Fastmail a few months ago and love it.
My tip is: Start simple.
- If you have any other Domains forwarded to Gmail forward them to Fastmail instead.
- Forward Gmail to Fastmail (i.e. add as an account including importing old mails). This won't get you off Google yet, but at least a backup and you can practically stop using Gmail.
- For any new registration, use Fastmail (or any of its random emails etc.)
- Slowly transition your old accounts.
Oh yeah. Or trying to highlight something including text further down, you want to scroll it a little bit and suddenly it accelerates and you highlighted the wohle page.