There are a million reviews here already for Chicago, so I will try to say what others haven't. I think it's the best major out there in regards to crowd support, course ability to really run FAST, and organization. I cannot say enough about this race, I love it so much, just wasn't my day...ended up laying an egg and running 2:58, but I will be back someday as I know I can do better. If you are waffling about this one _ DO IT _ the whole city embraces you, it's not a big city hassle, but it's a big city marathon, and a great field.