I've seen more operas there than rock shows but it's been many, many years since my last time in the place. Have no idea what kind of condition it is in now.
It's an old style classic opera house. Much smaller than DAR or the Myerhoff around the corner. At one time it had a very, very good reputation for being acoustically perfect so if they have a good soundman, it should sound nice. It's very nice if you don't mind a seated venue with old world charm. Those who have to be up on their feet right up at the stage will hate it though.
Just get yourself in a mind to go chill out and relax to the music and enjoy it for what it is. You may just end up liking the place. I saw Pink Floyd there twice way back before they got super big and it was great just sitting back and spacing to their music. Hell, even most of the band members (if not all) were sitting while playing. Save your up and party modes for after the show and go to some place like the Club Charles, The Depot, The Metro Gallery (all on the same block of Charles St.) or even a more intimate stop at the Mt. Royal Tavern with all the uber arty types on Mt. Royal Ave..
