I ran MCM 2019. It was rainy and windy-ideally the conditions every runner dislikes, but the crowd made up for the horrendous weather.
Pros:
You're running Washington, DC. The sights are incredible!
The crowd is incredible, and when I got hurt during the race, they were what kept me from not doing a DNF. There's so much energy and it is infectious.
The shirt this year was tremendous-which made sense given that 2018's was a disaster, and the medal was good, too.
Motivation is not lacking. When you're limping along and see a double-amputee motoring along, needless to say you're not going to quit.
It is one of the largest races in America, I'm not surprised that people find it hard to enter via the lottery.
Cons:
The expo is nice, but nothing extraordinary, which kind of surprised me given the size of the race.
It is a little bit of a walk to the finish festival, but the festival is nice and the experience there is great.

I would absolutely do this race again, if not for the fact that the conditions this year were brutal and I would love another shot at the course. I ran a 3:50, but it was almost 30 minutes below my typical time.