This was my first Hot Chocolate Race!
Unfortunately I was unable to go to the expo, since I had to work. The race allowed me to pay $15 to get my packet mailed to me, which made things easier. I received my packet in the mail about 2 weeks before the race. In the packet, I received a very comfortable and great fitting sweater/jacket.
A few days before the race, I purchased parking close to the start of the race with the ParkWhiz App. I got parking for about $12. This was considerably cheaper than if you arrived race day to get parking in some of the nearby garages.
The race guide was very informative, and offered maps and descriptions to locate gear check and the start corrals of the race. If this wasn't enough, they also had volunteers stationed throughout the area to help. They also had a very easy gear check as well as plenty of port-o-potties.
The start corrals were intense! Make sure to give yourself plenty of time if you are in the preferred corrals. The open corrals appeared to be a little easier to access. Also, if it is a particularly cold day, make sure to bring "throw away" clothes. Just because the wave starts at 7:30, doesn't mean you do. I was in corral "F" which was in the preferred corral, which was supposed to start at 7:30. By the time I got to the start line, it was 7:50. Luckily it was warm enough this year so this wasn't an issue.
The announcers at the start of the race were very entertaining. They kept the crowd riled up and ready to run. If you want to run this race competitively, I strongly recommend getting into the preferred corrals. The further back you start, the more congested the race feels. I ended up zig-zagging quite a bit, especially during the beginning.
During the race, there were 4 different chocolate stations. These included chocolate chips, strawberry marshmallows, m&m's, and chocolate marshmallows. They also had regular aid stations offering Nuun and water. The volunteers were very supportive and excited to be helping out.
The race route was very unique. We had some beautiful views of downtown Chicago, the skyline, and soldier field. The route ran around Grant Park, down Michigan avenue, and south around Soldier Field. As I finished the race, volunteers were handing out medals in the shape of chocolate bars. It is a very "sweet" looking medal :) They also had nuun and bottled water at the finish line. To get the rest of the post-race swag, you had to walk further down the road to a post-race party area. There was a live band playing along with tents set up serving all the post-race chocolate delights. The celebration mug held hot cocoa, fondue with dipping supplies of marshmallows, banana, pretzels, and a rice krispie. They were also considerate enough to add a wet wipe, since the fondue was a little messy.

To sum things up:
Pros:
+Swag! Awesome sweater and medal
+unique venue
+All The Chocolate! During and after the race!

Cons:
-parking can be expensive
-congestion during the race

This was a very fun event, and it was great seeing so many families out at the event together. I hope to do this race again!