I believe there was a case where they complied with law enforcement to hand over user data, and although the contents of the emails were unreadable, the header info and subject was.

I'd say it's as safe or safer than most things, though it still requires javascript to use, which that alone has some people leery of it.

I use protonmail and personally I'm not too sure on it myself, so i switched to https://secmail.pro and never had any issues.

I've been meaning to check that out. What do you like most about it?

No. We can't see its inner state. They'll do all unsafe things that we can do.

I just like it's simplicity, the captchas can be a bit of a issue but it's never been down for me, always worked like a charm.

SIGAINT was a great mail provider on TOR but it went offline a few years back now and never resurfaced, I was thinking of actually setting my own TOR mail server up but never got round to doing it.

I've never had any issues with Protonmail no, but I wouldn't trust them with sensitive information, Secmail is a TOR email provider I have used for a long time, and never encountered any problem unlike with SIGIANT when that was around.

I'll happily use protonmail for clear web activity and a TOR email provider for my TOR activity, which I do anyway.

Sorry if that wasn't clear enough.

Nobody uses email so who cares.