All in all, it went superbly well. Although the last 10k have tainted my memory and the soles of my feet are very sore/bruised. Apparently each foot hits the ground 20 thousand times in a marathon. Ouchie.
I kept finding myself grinning inanely during the run, from ear to ear, all the way upto mile 13 or so. After you cross Tower Bridge, you can see Big Ben to the left and thats only a mile from the end. So close! But the course turns right instead and you end up running away from the finish line. That's pretty annoying and thats where my smile left me.