I LOVE big races. I love giant expos and I love lots of crowd support.
The only crappy thing was the HEAT dear Lord. However, Chicago did what they could with LOTS of aid stations about every mile and each station was like 2 city blocks long. The fire departments had giant fans hooked up to hoses for misting stations between water stops in the back half of the race.
That last hill at mile 26 is total bullshit for the record though.
It's a world marathon, its only something you can experience, not enough words to really explain it.