I went to my first opera ever here, so this is not an expert review. However, the opera here is…read morequite reasonably priced, 10 euro tickets are sometimes available. I saw Carmen, and am going to see Calisto.
The theatre is modern and relatively intimate, but on the main floor there is no center aisle, so you will have to stand up a million times when people before the opera starts and at intermission.
The quality of the production was good, Carmen was done with a modern theme so there weren't any fancy sets or costumes, but the singing was good (for a novice ear at least).