I saw it yesterday too. I've seen it once on stage (ENO in London) and, of course, this was the same production but with completely different singers except (I think) for Janis Kelly as Pat Nixon. She's done various roles for Opera North and was the Prima Donna in Rufus Wainright's much-panned Prima Donna. Good to see her at the Met.
I know a fair bit of the music, and it was just as riveting as last time. The best singing (IMO) was from Russell Braun as Chou Enlai. James Maddalena IS Nixon, but he got a bit croaky as the opera wore on. Robert Brubaker as Mao and Richard Paul Fink (Kissinger) were good, too, and it was nice to see Adams himself conducting.