In short: A once in a lifetime experience In full: A personal challenge: to run my first marathon at 50 and raise some money for two great charities. I enjoyed it so much more than I thought I might just have to do it again.
As others have said, great organisation with so many little things coming together. It was great that the marshalls had a word of encouragement when you collected water -- how many thousand times did they do that? So much encouragement and entertainment from the crowd.
Thanks to the RW pacers at 10 mins per mile. They stopped my from going off too fast and I kept with them to Tower Bridge when I lost them in the crowd and settled to a slower pace. Managed 4:38 with which I was really pleased given the heat. Have little recollection of miles 21 to 25 --we were all finding it tough but Big Ben to the Mall gets you going again.
The finishing line arrangements best of any race I have done, I was through in no time but Horse Guards Parade was congested. I doubt much can be done given the numbers, but I had a miserable 20 minutes until I found my family.