In reply to jamesoneil:
I found it in better condition underfoot than most of the popular paths in the UK. Either the numbers using it are fewer, or they do a better job on erosion management.
There was only one short section on the first day from Les Houches where the path was narrow and exposed (with a wide gulley on one side), and where a cable had been fitted alongside, presumably for winter use. This section didn't bother me at all, but a couple of my less experienced companions were a bit disturbed, and held on to the cable. IIRC, it was in the section just N of the Torrent de Bionnassay, heading S from the Bellevue lift.
Thereafter, I can't think of anything that was particularly exposed. It was obviously fairly high, but not exposed.