There was a great session at Ignite 2018 helping you to find the right authentication method whether is is ADFS, PTA/SSO or PHS/SSO.
There where 2 interesting announcements in that session:
- Seamless SSO will support Edge Browser shortly
(Currently only possible with hybrid join)
- Staged migration of authentication methods will be available in October as an public preview. So you can change auth method user-by-user.
Watch out the video Choosing the right authentication method: