I've done it twice including last year. Be sure give yourself a lot of time in the morning to get through security check points and into your corral, more than usual. It just takes forever, especially now after the Vegas concert shooting when they beefed it up even more. So if its chilly and you're thinking of spending extra time indoors, don't. Other than that, its pancake flat and crowded. Spectator support is incredible, especially the first half and last few miles up Michigan Ave. The second half of the course I find boring, just some uninteresting neighborhoods (but I live and grew up 30 minutes away, so it may be more interesting to you). There's one small hill just before the final turn to the finish chute that people curse, but its really nothing. Have a great race, its as fast as advertised! Just hope the wind isn't out of the north or the last ~6 miles won't be fun.

I ran last year and am going back again this year. I’m 44 and ran a 3:06 from corral C, so pretty similar. Here are some impressions from someone who’s only done the race once:

1. Be prepared to not count on your GPS to monitor your pacing. Mine didn’t work for probably half the race.

2. The opening 10K is very crowded with a number of 90 degree turns. I never had more incidents of getting my legs clipped in a race than I did in the opening miles at Chicago.

3. They start the PC racers before the first wave. So, be prepared to come up from behind PC athletes and their guides in the first few miles who are running much slower than you are. It was very difficult to see and anticipate them given the aforementioned crowds. There always seemed to be a narrowly averted wave of disaster when a group would come upon them and people would suddenly swerve (without looking) to get around them.

4. The pace groups are good if you’re looking to run a specific time. For some reason, however, everyone seemed to want to be right on the feet of the pacers.

5. The crowd support is great.

6. The course is flat. Really, really flat.

7. The buses to the expo from various locations downtown (e.g. Niketown) are very convenient.

That’s all I can think of right now. Have fun and good luck. I know I’m ready to be done with training and can’t wait for the race.

Totally agree with the two previous posts.

I've ran it 3 time and volunteered twice (aid station and medical icu). Be prepared for anything weather wise. It's been cold and wet and hot enough that they had to shut it down. They were not prepared at all. The aid stations ran out of water and my volunteer group was running into the restaurants filling up the coolers. However, they've learned a lot since. When I was in the med tent, I got to talk to the medical director and they are prepared for anything. He also coordinates disaster relief.

GPS signal sucks in the city (I never have a good signal which includes running, driving and OWS by the lake), but pacers are pretty good.

No real surprises except the little hill over the bridge at the end. Also crowd support awesome, but crowds drop off after Chinatown around mile 22. It doesn't pick up until maybe mile 25.

I'll be driving in from the suburbs and parking at Millennium Park.

It's my first time running it, as well.

Any suggestions on what time to get there? I assume parking and crowds really have to slow things down.