I am uncertain about the two-factor authentication feature. I have had integrations with other Proton services and have used Proton VPN once, though it has limited features. Simple Mail, which was acquired by ProtonMail, has been very useful for me. The pricing is moderate. I have not used any paid services from ProtonMail. It is not very costly, but I have not used any premium services. I am a customer of ProtonMail. I would rate ProtonMail an eight out of ten due to their transparency and the utility of their simple login feature. My job and company name should remain hidden.
