In reply to simplyawful:
I did the Norman Neruda route on the NE Face about 30 years ago, the one which follows the narrow rock rib on the upper part of the face straight below the East summit. We kept well away from the face until directly opposite the rib to minimise exposure to serac fall and, especially once on the face, it felt safe enough but someone above suggests that's no longer the case. Certainly the Grenz Glacier which we approached it via is the most wildly crevassed glacier I've been on in the Alps, but again, I don't know what it's like these days.
We soloed up to the foot of the rib, it would have been very slow to pitch this bit but you really wouldn't want to slip, it's probably a good 50 degrees so self arrest isn't realistic.
You can follow snow to the left of the rib all the way if conditions are ok (the Welzenback Variation) but we took the rib for interest's sake. It was mostly about Scottish II and III mixed but I thought the crux pitch was quite hard, probably Scottish IV mixed. It was almost at the top of the rib and so over 4000m altitude which didn't make it feel any easier!
We descended via the East ridge to the Lisjoch which was quite exposed but fine from a cornice point of view but we were being chased off by an approaching storm so didn't hang about to savour it too much.