I went to this performance purely for completionist reasons as it was of an opera that I had not previously seen. Having endured three previous attempts at the genre by Philip Glass my hopes were not high (you can read my thoughts on the Barbican Einstein on the Beach and ENO's Satyagraha). This is not as interminable as Satyagraha, but it is not great opera.
The problem on this occasion is with the work itself. I concur with others who have argued that Glass uses more orchestral colour here (particularly brass) than in other works of his I've heard. He also seemed to me more willing to allow for fleeting melody. This can't finally transcend the basic limiting character of Glass's repetitions – this is music that dramatically to my mind either goes nowhere or goes to the same place over and over again with diminishing effect – but it does make them more bearable. Influences of greater composers also seemed more evident here than in other Glass operas – Wagner for example (the programme note cites Purcell) with the overall unfortunate effect that his weaknesses against their greatness are the more exposed. All that said the approach does work better here than in Satyagraha, because the subject matter lends itself to this kind of style more readily – particularly in the heavily ritualised Act One.