I have enjoyed going to symphony hall for years, even before the remodel a few years ago. It is spacious and the acoustics are a complement to whatever music is being played. I love the orchestra and the chorus that sometimes accompanies as well as the special events and guest performers.
The auditorium is clean, the seats comfy, and the restrooms (at least, the ladies' room) is clean. It's convenient to parking as well as restaurants before and after the performances.
I love going there and people watching before the shows. Sometimes they have special entertainment in the lobby prior to shows; e.g., at one time there were people showing off their skill in ballroom dancing and some were quite good.