If you are concerned about keeping your feet warm…
Use: Waterfall Ice Climbing, Mountaineering
If you are concerned about keeping your feet warm double boots are the way to go. I just got back from climbing in the Presidential range and it was cold. It was my first trip with them and not once was I concerned about my feet. The Salomon Pro Thermics were great. And they were light as compared to the Invernos I was used to.
Another great feature is how easily the boots lace up. If you like your boots tight the soft tongue allows them to get nice and snug. Another great thing about the soft tongue is on the decent your shins don't get all bashed as they often do with plastic doubles.
I'm incredibly happy with these boots and would without doubt recommend them. I can't wait to get back out and use them again.