I have done this race 3 times, and it is by far one of my favorites that I wish I would be able to do every year.
It has been going on for 36 years and is a huge race about 18000 runners and walkers, and is also a festival.
It is a slightly hilly course. you start going up the Brady street hill. Which unless you get into a fast corral expect a lot of walkers. I put myself in the 9 min pace one year and ended up with everyone around me walking up the hill.
The awesome part is since it starts going up hill and you finish on a downhill with a great view of the quad cities.
The crowd support is one of the best crowds out there, people offer you ice, Popsicle. It is a huge event for davenport. People out in their yards playing music and dancing, people will hand you shots, beer, bloody marys.
It is an awesome race. One of the really cool things they do, is beat the elite. So my best bix time was 1:02:07. Its in July so its usually really hot, making it hard to get good time on. What they do is. They take an Elite runner and give you a head start based on your finish time. so if the elite time was 34 minutes, they I would of had a 28 min start and if you finish before the elite you will 3500 dollars. There is a lottery for that and one person gets to try to beat the elite.
you also get a pin every years you do it.
They also have a costume contest, because running 7 miles up a hill on a hot day is not a challenge enough. lol.

So, when I ran this race it was my first marathon in 8 years. I had trained the previous fall and injured myself. It was before a lottery was needed to get in, I know two years later they added an lottery. The year I ran it was a pretty good price point, it was $75 dollars cheaper then the Chicago Marathon, which made the 11 hour drive worth it in my mind.
What I liked :
Scenery, awesome so pretty, my favorite part was right before and after George town where there were a few smaller hills, a river and trees. I even saw a joggler, a person running with juggling. People kept telling me it was hilly, I am from Chicago where there are zero hills, and I remember a few hills but nothing to stress out about.
I loved all the Marines cheering you on. It was so inspiring and added to the atmosphere It was on Halloween and many spectators handed me candy. I am not an expo person,and I remember really enjoying the expo.I even purchased t-shirt at it.
FYI no one can come to the starting line with you, you need to get there pretty early and you will be id'ed since it starts at the pentagon.
What I didn't love,running through the mall area there were a lot of spectators,and it got crowded, Then around mile 20 you enter this bridge with no shade or aid stations. I gave up on the bridge, I had been under my pace goal. I stopped sat on the bridge for a while and contemplated life. Everything up until that point in the race had been great but getting on the bridge, the lack of shade, the lack of crowd support right around mile 19 or 20 broke me a little.
At the end it seemed like I walked forever to gear check, bonus part or creepy part because it was Halloween when I passed the med tent walking to meet my family near gear check it looked like crime scene with melting clowns, and pandas and all kinds of injured people in costumes.
Overall I really enjoyed the experience, It was my first time to D.C. I found that walking 10 miles the day before so I could see the zoo a bad idea, but enjoyed walking around the day after. As a bonus DC has several great bakeries that are great for recovery.