Been here to see the Nutcracker Ballet and recently the Cirque de la Symphonie. Both performances were very enjoyable. I highly recommend sitting up as close as possible. It is a pretty small stage. There are multiple ways to get to your seats so it doesn't feel too crowded. The seats are pretty tight, but overall the venue is clean and feels updated.
There is a parking garage directly across from Symphony Hall-$12. You may want to check if there is anything else going on that night, because if there is, it may be full and you may have to take a little walk.