The 2012 race was my second Dam to Dam race (planning on running the half this year). At the time it was still a 20K. I loved the experience of the race. The shirt was fine, the socks were better. The aid stations were very well run with plenty of water/PowerAde to go around. But the best part were the people. There were always people lined up along the route cheering us on. Running from the dam to the city makes for awesome visuals - both rural and urban. Watching the DSM skyline come into view is a great experience.
For the most part, the race is downhill. There is a beast of a hill (Memorial hill) around mile 7 or 8. I will do a better (more complete review) after the 2015 race!