In reply to TobyA:
I think the experience is pretty weather dependent, I did it as an unsupported walk/run in June. Set off at night 21st June and when I got to Kinder the downfall (which I was used to finding by sound) was just a dribble, it was my first water stop and took forever to get 500ml. The next day it was scorchio and I got heat exhaustion/ very mild heatstroke that made an uncomfortable night after 50+ miles. I planned for ultralite cold and wet and got hot and dry, water much harder to find than usual on sections I knew quite well.
A friend of mine did it the next year, as a supported run and thought he'd do it in April, after my experience. He got snowstorms almost all the way and hated it.
Camping is the way to go or else you waste too much time off trail or get full support and get driven off to a nice bed each night.
If I was going to do it again I'd probably try for 3 weekends, unless the appeal is the week long trip.