I only ever used Proton for a few secondary email accounts (compartmentalizing between personal and online) and I started transitioning shortly before they got in the news for statements.

My main problem was that I realized that I couldn't use email forwarding (or at least without paying for a plan, I forget), and I couldn't manually handle it with a third-party client without paying for their bridge, so unless I wanted to have to open and log in to an old email address for the rest of my life, I basically had to pay to deprecate an email address or move to another provider without risking any future emails to the protonmail address being lost, and I wasn't in a position where paying was an option for those addresses. Now I only register single-use throwaways on Protonmail (despite their efforts to detect and stop it).

• The Android widget (not app just the widget) does not have a monthly view.
• There is no office suite (I don't know why this surprised me but it did).

Generally it's been an overall positive experience.

I looked to see if I could get by replacing Photos with Drive in Proton. Whilst I can upload stuff. Videos greater than 100mb need to be downloaded to be watched. I guess because Google process videos to allow them to be streamed. Sadly a deal breaker for me :(

I feel like the Android client for ProtonMail is really slow. Switching folders is painful.

I also tried sharing calendars with my wife who is still on Gmail and didn't have great luck there. I decided I'll just forward invites to events to her, though I haven't had a chance to test that.

honestly i would recommend keeping google calendar. proton calendar just wasn’t cutting it for me so the only google app i still require is calendar

Proton bridge is scam - it only pretends that it works. I have been trying to get a support that it doesn't sync & delete e-mails correctly for 2 years and the only "help" was to clean the cache and wait 2 hours for resyncing...