The more modern of the theatres that the Mirvishes have to put their productions on, the Princess of Wales Theatre is the sister theatre to the Royal Alexandra Theatre found just east of it on King St. W. Seating 2000 or so, the theatre's first production was "Miss Saigon". I saw that production and have since tried not to hold it against the theatre.
The theatre itself is eye-popping. The glass front provides a great view of the street, and allows for natural light during the day or the streetlight-lit darkness at night. The theatre itself is a great design, with great main floor, mezzanine, and balcony seats available. As far up as you may be, you always feel like you're part of the show.
The facilities are well appointed allowing for good group outings if required. The bars for pre-show and intermission drinks move with a great pace to allow you to get a beverage without risking missing the performance. Unless it's "Miss Saigon". Then you may want to hit the bar heavy.