Protonmail probably the most hyped, but personally I switched to Tutanota. I like their commitment to open source - you can build their webmail client yourself. They support full text search (unlike Protonmail) and also 4-5x cheaper than Protonmail/Fastmail, if you're fine with their cheapest 1GB storage plan.
ProtonMail is the most promising.
I've been using ProtonMail and ProtonVPN for over a year, paid subscription. Both web and mobile client is ok, not great. On desktop I use Outlook (Windows) and Thunderbird (Linux). I like the domain @pm.me.
Overall happy with the service. Customer support has answered questions competently.
Protonmail has a huge gap between promises and what's delivered. Their IMAP bridge is slow and buggy, their mobile app hasn't been meaningfully updated in a year, and even as a paying user they put upsell ads in the sidebar, above your own folders.