Hey hoggy and jim,
I did this last year and really enjoyed it. Fantastic atmosphere, great course, great music around the course, would have gone back this year as deffo fave marathon I have done..just doesn't fit with my training this year.
Also had lots of great info from mr Neil jones 26 (hope you well Neil, thanks again for last years low down).
If you search 'Madrid marathon 2012' in the forum search bar there is some info on there.
I would say, go pasta party it's great, watch out for where 10 k splits off from marathon, weather was ok so try not to worry too much ......and try not to use too much energy bopping to the bands as you go past!
Yes there is an incline at the end and it is a proper grit teeth and go for it finish, but again a brilliant atmosphere!
Just think of the nice cold San Miguel at the end! Have fun!