United will prioritize the PS departures out of EWR, and they will not be subjected to the same delays as some other flights. I'm not sure I'd agree that delays at JFK are less across the board. I've been part of some pretty insane delays there while EWR has ben flowing just fine.
I LOVE this change. For folks that are primarily United flyers going from West coast into Europe (other than London, Paris and a few others), you now go lay flat the entire way..