Chicago is amazing! I wanted to run a World Major without having to travel too far. I'm lucky I only had to drive from Ohio.

Pros:
Amazing course thoughout the city
Sheer number of people cheering you on
You are always running with someone without feeling like your too crowded
Expo to die for- every major brand was there, plus I got to meet Deena Kastor and Joan Samuelson!
Organized start and finish line.
The different neighborhoods made the race really interesting
Nice Nike dryfit shirt in neon yellow this year (nice for hi-viz, although a long sleeve shirt would have been nice since it's getting closer to winter)
Cons:
lines for portapotties although they had plenty
long lines for taking the shuttle to and from the expo from the Hilton
really can't say much more than it was pretty freakin' awesome! I will definitely do this again!