There's nothing a cabin-fever addled New Yorker needs more than the chance to get outside and listen to some good music. SPAC would be better, however if they allowed coolers, as they do with the Jazz Fest. The beer garden truly is ridiculous and they need to just lighten up and serve booze.
I tend to get bored in arena-type settings where you inevitably have to stand up to watch the show because that's what the people in front of you are doing. SPAC is a great alternative to that; you can walk around, meet your friends, and play a game of cards if the guitar solo is going on too long. Beautiful setting, but die-hard band-fans won't enjoy it, because they'll be too far away from the stage for good visuals/acoustics.
Pros: Scenery, Social setting, OUTSIDE
Cons: Acoustics, View of stage, Losing car in park