I have used their email for years without issue.
Don't choose a service based on politics though. Choose one that supports privacy in the way you need. Proton is advancing the world in privacy in a really great way. That's what we should be supporting and focusing on. It's not like a crappy VPN company saying this is what you need to be private. They're product is proven and we need that to spread if real privacy is ever going to catch on. Put political differences aside and let's make the world a better place.