I've been with them for a couple of years now, and happy. I get the VPN on my plan too, which saves me paying for it elsewhere, plus I trust Proton already.

In terms of e-mail, it's pretty good. Nothing special, but the fact that it's E2EE and they've figured out a way for me to still search the contents in the browser is pretty cool. I use it mainly with Apple Mail though.

I don't use the calendar and contacts. Not sure why, but I remember I tried them and they just weren't as useful as Google's.