I too have been to many tennis tournaments around the world and the US Open is not my favourite. It's New York and Kelly is right about the subway, the people ( yes some are quite hammered) but that stadium (Ashe) is very loud all the time. It's far too big for tennis and because it's New York and people are loud , drunk or not, it's hard as a player and a spectator to enjoy a good match. 
I'll go a step further and say it's louder than watching and NHL game live. Actually, tennis in New York reminds me of a basketball game without the music. Things have changed. Not sure it's for the better.