I completed my first marathon a week ago and finished in 3.59, which is 9.09mm. I had done most of my LSRs at 10.10mm. This was not a deliberate decision, I just went with what felt very comfortable on the training runs. I did the last couple of long runs at 9.50mm, but this was a deliberate effort to go a bit faster to see how it felt (tough). During my long training runs, I generally felt very relaxed until the final quarter, when I tended to suffer from very fatigued legs, possibly due to my training runs covering a lot of hills (hilly where I live).
I ran very even splits of 9.09mm in my race and I felt very relaxed, perceived level of exertion about 5. My legs felt tired from about 20 miles, but cardio wise I felt good.
I'm not quite sure how I managed to feel so good in my race, compared to training runs. I bit of it was down to the race being a flatter route than I'm used to and the weather was cold which suits me. Oh, and a bit of luck!
I hope this helps.
Edited: 06/05/2012 at 21:39