I've been using it as my primary email since around May of 2017. I can only speak for the web and Android versions of protonmail, and those work pretty well (co

I've been using it as my primary email since around May of 2017. I can only speak for the web and Android versions of protonmail, and those work pretty well (comparable to the gmail app and gmail in the browser). I'm using the paid version of protonmail with a custom domain, giving me the ability to somewhat easily switch to a different provider in the future if they go out of business or end up losing my trust.