The Sheraton is a gorgeous boutique hotel located in a lovely square just across from the new opera house and adjacent to a large shopping mall, the Eurovea Galleria.
You can spot a side entrance to the mall in the lower left hand corner.
The new opera house, where we enjoyed Tosca, is not that large - we would guesstimate it as not much more than a thousand. There is literally not a bad seat in the house, but if one can sit in Row 3 center for 20 Euros as we did, why consider the back of the balcony?
The Sheraton bar offers a wicked Happy Hour, with not only drinks but tasty appetizers on sale at 50% off, all in a lovely setting. A couple of Tanqueray and tonics each and this plate totaled less than $20. Try that in most big-city hotels.