Since buying mine I've used them in Switzerland in the Grimsel Pass area, and in the Lofoton Islands. In both cases they are great for taking up long multi-pitch routes since they weigh nothing. You can also climb straightforward slab routes in them since their grip is excellent (though leaders don't appreciate this when you walk up their routes as a second...). They are also good on wet rock and grass (unlike, say, 5.10 shoes).
The only disadvantages are exactly what you expect:
- no ankle support
- the canvas sides absorb water, so don't start walking through wet vegetation or mud and expect your feet to stay dry. Of course they do dry out fairly readily though.
I haven't had them long enough to predict their longevity, but they're holding up fine so far.
I definitely recommend them for these uses, but they're not going to replace approach shoes for long, wet or rough approaches.