In reply to aindris75:
Hi aindris75
I did the classic traverse ascending via the Mittellegi (Difficile) and descending via the South Ridge (AD) a few summers ago and it is an outstanding adventure. Ironically the technical "crux" of the whole route is encountered on the first day on the slab (about VS in big boots) immediately above the Challifirn Glacier, after leaving the Eismeer railway station on your way to the Mittellegi Hut. It is an amazing hut in a spectacular setting and the old boy who runs it is a legend. If there is a settled spell of weather on the way, make sure you book a few days in advance as it gets full very quickly!
If interested the following is a wee film of our 2 day tour which shows getting to the hut + that cheeky crux, the Mittellegi hut and on the super-exposed ridge itself, which is thinner than an anorexic After Eight mint in places...
Hope this helps!
Dave