In reply to Frank Boase:
Only the northern half, SN from Vizzavona in 2011 for what it's worth now, with three not very outdoorsy teenagers, who all coped admirably despite that it is very hilly. There was only actual crying once, on the first big ascent up from the railway station, and that was when she fell over. The next day, when we got really soaked, that and how we'd (allegedly) mis-sold the whole thing to them were just stories to entertain the rest of the hut when finally we were dry and warm. If you set off each day when everyone else does, and do one hut at a time, you typically arrive in the early afternoon, and then can spend the rest of the day reclined on a rock in the sun with a tipple of your choice. So it's that tough.
We stayed in the refuges, which I liked but which latterly have acquired a reputation for bedbugs. Camping at the refuges is an option, including hiring tents, I think. I'd probably do that, next time.
Eating in is really expensive and not always very good, especially the breakfasts.
edit:
The Cicerone Paddy Dillon guide is OK, but the French and German guides had better maps.
Going SN you are in the minority.
Personal highlight: Scrambling up and down Paglia Orba next to Ciottulu di i Mori before everyone else got up.
Post edited at 15:18