There's nothing like running through this great city with 40k of your closest friends. This is my second year running the Chicago Marathon and I was blown away again with how well a large-scale event can be executed.
BoA and all of the sponsors really make the experience special. They do a great job of getting participants all the information they need before, during, and after the race. The expo experience, while not extremely convenient to get to, is so much better than going to Navy Pier (as many other reviewers have noted).
Advice on raceday: get in your corral early. While well-managed, it does take some time to weave through the security checkpoints and corral gates. Bring a layer to ditch if it's chilly definitely use the facilities beforehand!
The course: this year a blue tangent line ran the majority of the course, showing the shortest possible route to run. While I was cognizant of the line, I used it mainly to set up for corners rather than elbowing people out of the way to stay on it. This is a flat, fast course that only suffered from a few wind tunnels heading south. The crowd support was much more consistent this year - it has been sparse in the past in the later miles. Great aid stations and volunteers all around. Do you best to give it your all up Roosevelt Mountain. Once you turn that corner it's less than 200 meters to glory!
Post race: the long walk down Columbus seems ridiculous but it does allow your legs to settled down and there's lots of opportunities to catch up with fellow runners for pictures, swag, and free beer (you don't even need your coupon)! I have not made it to the 27th Mile party either year so I can't comment on its execution.
My experience: This was my 3 marathon this year and 4th including Chicago last October. Each passing race I've gotten closer and closer to my BQ goal, falling minutes and seconds short every time. Finally, Chicago, 2014, I can say I have qualified for the Boston Marathon with a time of 3:02:06. I can barely put into words what this journey has been like but I'm overjoyed to say I conquered it at home! I will never forget the feeling of crossing the finishing line, knowing I had put my body and soul into this race.

Well...this was the first race that brought tears to my eyes (and not in a positive way). More on that later.
This small, extremely focused race is perfect for those trying to qualify for Boston right at the registration cutoff. The 8, roughly 3.25 mile loop course has great scenery around the Fox Valley river. There are two aid stations on the course with water, Gatorade, and Clif shots. One of the coolest parts of the race was the elite water bottle table for ALL runners. Simply put your bib number on your bottle and volunteers will have it ready for you each lap (they'll retrieve it from the drop zone - just no refills). The course support is fantastic for a race limited to 300 participants. For those spectating, it's a real treat to see the athletes 8x without moving! Definitely check this race out if the spring and summer marathons didn't quite get you to your goal.
For me personally, I missed my BQ goal by 53 seconds and will be attempting again at Chicago. I won't soon forget the feeling after this race. It's tough to not internalize everything and dissect all of the details. I know I'll hit it, it's just unbelievably frustrating at this point. On. To. The. Next.

I'm torn. PR'd my half by 2min 28sec but this is not a great course. There are too many bridges/underpass sections and I have a feeling it gets very congested on the path later in the race. I did not see bands until at least mile 5 or 6 (city regulations I heard). There were stages but not many performers. Aid stations were great and the volunteers were energetic and helpful. There was great support between miles 10-12. Really loud AC/DC helped re-energize me as we neared the finish. It's hillier than one might expect for a downtown race because all the entrance/exit ramps add some elevation changes. Another opportunity was the 5k/half finish line set-up. I think we were verbally instructed to stay right/left depending on which race we were doing, but it did get a little congested. It may not have effected the majority of the runners, but still something to look at for future events. I'm incredibly happy with my personal results but it's tough to give this race a super positive approval rating. It is a well-organized race for 17k runners and the post-race rivals most events in the city. We also got lucky that it wasn't too hot and the cloud cover was amazing.

Terrific weather this year for the SF10. I had a pre-race goal of sub65 but a nagging knee injury threw a wrench in the gameplan this year. I paced the first half well but lost a little gas heading into the last 3 miles. Still finished less than 10 seconds off goal but probably could have pushed it a little. As always, the organization of this race is fantastic. Awesome swag/medals, a killer cover band at post race, and super great volunteers. If you haven't, please sign up for this race next year. It's such a great experience!!