I've been using Proton for my businesses for years. I have a legacy visionary plan that is _very_ generous based on current limits/prices. I don't have any plans on going anywhere else!

My only gripe has been searching email is a pain.. you need to download/index the data locally (due to encryption on the server), and the search quality isn't great. I am confident they will improve the search algorithm/filters in time... but you'll still need to download all of your mail to search (no way around it I know of unless some clever crypto people can figure that one out...).