I love running Chicago! I ran in 2010 and 2012 and it demonstrates how different weather can be. In 2010, it was 73 at the start, 93 at the finish and I was just trying to finish without the black flag coming out. In 2012, cool, 50* and a PR. Flat and fast course with minimal hills if any. You see a good bunch of Chicago and the fans are phenomenal. Additionally, aid stations are well done.

Expo: fast and painless, although, their moving to have runners pick up their own bibs. Lots of different vendors and races to browse through. Also have a t-shirt exchange option to take advantage of.

Use the El to get around, it's easier than trying to drive. Overall, awesome race, and a must do eventually for any runner!