I have watched and an Italian Opera in here. Inside was really good and has good atmosphere. When I will come again to Kharkiv, I will most probably visit this place again to watch some opera or concert.
The building is quite unique in the architecture, great example of constructivism style. And inside if you will decide not to go straight to the concert hall you can get lost, it's almost a labyrinth)
And the ballet or opera itself are very good. Definitely can recommend to visit if you have time. Nothing special, but there are just few...