Personally, I was less than enthralled by Anna Bolena; I found it slow and dull. Netrebko's voice was as beautiful as ever, but I think she was holding back on her almost-coloratura performance, saving something for the mad scene at the end. Up to now I had considered her a good actor, but today she showed Great Anguish by either staggering across the stage or by grasping her middle and bending over as if she had a bellyache. Old-time hammy operatic acting.
New-ish tenor Stephen Costello has a sweet voice, but he had to struggle with the high notes. Elena Garanca was originally scheduled to sing Jane Seymour but she decided to have a baby instead, so the role went to Ekaterina Gubanova, whose voice has a harsh edge to it that I find unpleasant. The ensembles worked well, especially the pre-Lucia sextet that closes the first act (played as a two-act opera). But for a story as loaded with drama as this one, the opera is curiously flat and even bland.
All in all...I was disappointed.