I have working with both Admin systems and I really love Sonata Admin (I think in this case it is a matter of point of view as opposed to the discussion about FOSUserBundle) over EasyAdmin.
Why I love Sonata Admin? Because it integrates with MakerBundle perfectly, the way you can extend the behaviors is really easy and it has seamless integration with S3 through SonataMedia and WYSIWYW editors through Formatter. Maybe the learning curve is hard at start but I prefer it over Easy Admin.
Thanks for your comment!