As we did the Chamonix-Zermatt trail last year en part of the Alpine Pass route (from Sargans to Lauterbrunen) this year, I guess it's nice to see the experience of others.
From both routes I definitely prefer the C-Z trail as it is more spectaculair in its entirety and it's more remote.
The Europaweg is indeed a bit delicate in places. If I look at the pictures, I think most of the avalanches already occured before august 2008 when we were there because the trails seem awfully familiar. As a result, some parts took much longer than exspected. The trail needs constant maintenance because it is so fragile. Buth it does make for a spectaculair trail. For those who can suffer from vertigo (like myself), it can be a bit frightening at times but I'm glad we did it. An we found a beautifull spot to camp just before the Europahut with both sunset and sunrise spectaculaur with all those 4000m mountains in the back.
I did notice the last picture from Roger with the avalanched trail but I do seem to remember that you're not supposed to take that part anymore. The trail goes down from there, circumvents the problematic part and goes up furtheron to meet the original trail. Still taking the old trail cannot be done by mistake since all the signs are very clear.
The Alpine Pass route is of a different quality. It does take you more through cultural Switzerland but as a result it's sometimes difficult to find remote places. Since we decided to camp all the way to Lauterbrunen, we did nearly every stage in 2 times. Ending each day in a village is not exactly what we preferred. Especially given the size of some of villages. We also took some buses. Ending each day in a village below 1000 meters and as low as 500 meters not only means a long climb up to reach the 2000 meters + passes but also that the first few hours of the day, you spend your time in the woods where you don't have much vision of the mountains all around. so from Sargans, we did the first part by bys. From Elm tot Altdorf, we did most by bus because there's a big road running through the same valley you have to walk through (except a few hours walking from the Klaussenpass). End from Meiringen we also did part by bus because my wife saw up against all those climbing in the woods.
Although it is a nice route, the first days, untill you reach the Berner Oberland, are just that: nice moments in the mountains but nothing spectaculair. From the Grosse Scheidegg, you get your first spectacular view when you first can see the Eiger in its full glory. Especially nice if you now all the background history about the mountain. I guess from there on it should be spectacular beyond Lauterbrunen just to Kandersteg and Gsteig but I can't comment on that since we havent done that part (yet).
Oh yes, in general the Benrer Oberland sees a lot of rain as it forms part of the northern range and as such is he first to meet the wet weather coming from over the Atlanctic. Wallis (C-Z route) is considered drier. However, this year, on the Alpine Pass route we havent spent more than 5 minutes walking in the rain so we can't complain about that.