Took them across rock, gravel, sand, mud, bog, black ice, green ice, white ice, snow, tree-roots and tarmac. Good grip all round, except on the black ice ; there, no grip at all (at all).
Since my last visit, the site is under new management, though I'm not sure exactly who is managing it. In any case, they've upgraded the welcome sign which is now a cheery green-white-and-orange mix, with quite a friendly font. All of which is slightly out-of-keeping with the rather serious warning being proclaimed by the text:

Paraphrasing: these two paths are dangerous, and not suitable for people suffering from vertigo.
You don't say?
The "escaliers métallique" mentioned in the first paragraph:

And the "crête exposé" described in the second:

Will put up some photos of the scenery en-route in due course.
Edit: here they are