I've now seen all three. I loved Ferryman and hated the other two. They're Sorkin and Van Hove each applying their standard lacquer to works that don't need it or benefit from it, and the plays are bad versions of the book and movie, respectively.
Mockingbird has been Sorkin-ized beyond recognition, and now plays for shock value and sanctimony, stripping all the heart and poignancy of the book. I saw it with a black friend who cried afterwards, not because the play stirred emotions, but because she was so heartbroken that a book she loved had been ruined so thoroughly by a constant, unnecessary stream of the n-word and black characters being used as teaching tools for white characters.
Network, only Cranston is worth seeing, and had there been an intermission, I likely would have left because the lights were hurting my eyes. And I'm not particular sensitive to that sort of thing; it's just a play where best thing about it is the set, and the set is only interesting for the first few minutes, after which it's literally glaring. If you adore Van Hove and want to see his schtick again, I'd wait and see his West Side Story.