This was...perfectly competent.
Branagh was okay as Poirot but could not match Suchet (who can?) The acting and cast were stellar in terms of renown and serviceable in terms of talent. The direction was nouveau and gorgeous. And the story (with some tweaks, I've gathered, from the original novel, but mostly just to frame this as a successor to Branagh's previous adaptation) is a bloody classic.
This felt like a very good cover band doing a Poirot adaptation. It was neither a great movie nor a great Poirot adaptation, but wasn't bad on either lens. If you're craving a whodunit, this isn't quite empty calories and is going to be entertaining.