The Opera House will be closed at least until 2016. I've visited it in 2011, it's really magnificent. Though the interior currently looks rather dark and gloomy. I could have a short glimpse of the result of the renovation works, in a small area the renovation was tested, and it looked great.
The renovation aims to restore the opera in the original appearance from 1748. Originally, the light green paintings were bright and glamorous. In the 1930s parts of the walls have been overpainted in dark green, and in the 1950s there was an ample use of oily wood preservatives which additionally darkened and impaired the paintings. And also modifications of the stage from the 1930s will be removed. Finally, air conditioning and fire protection required by Unesco/ICOMOS will be implemented.
This website gives a good impression of the interior:http://www.schloesser-bayern.com/fileadmin/sites/schlbay/pano/ofra/bayr-opera/pano-sv .html?pano=fr/vor-oper/pano.xml