In reply to southernclimber:
I did this route over 25 yrs ago so some of the approach details may have changes especially the trek up to the hut. The Lindsay Griffen guide to the Bregaglia stated that the Gaiser-Lehmann route was one of the best in the Bregaglia and rivalled anything of comparable length in the Western Alps. The route was climbed on the same day as the Cassin route on the Badile, and is now recognised as a popular classic. Everyone has commented that the lower part is scrappy and route finding problematic but the route sheltered from rock fall.
The big rockfall which affected the Cengalo happened on the ENE face and took out most of those routes as well as changing the walk up to the hut.
One reason for the lower part of the route being loose is that it probably lay at the upper limit of the glacier and so was affected by freeze thaw action more than further up, which is steeper and so cleaner. Also as the Cassin route became more popular (5 North Faces etc), traffic which would have cleaned the lower part just didn't happen and so the route remained dirty. As the route got a reputation for being dirty people didn't do it and headed over the the Cassin, which cleaned up, had a well travelled path, known belays, in situ gear, (the popularity circle). Lots of topos and articles of how to climb the Cassin are around on the internet. In the right conditions the Cassin can be done without axes, boots and crampons with the abseil descent down the North Ridge.
Doing the Gaiser- Lehmann route is an old style 'up and over' route with a long and scenic return from the Italian side. If you do do the route, spend an extra day at the Gianetti Hut and do the South Ridge before walking back.
Good luck