In reply to gethin_allen:
> Neither of these are very warm boots so I'd depends on what you have in mind and how your circulation is.
Which raises a good point, which is sizing for your sock. For technical scrambling a lightweight sock will give you more precision, whereas winter mountaineering will want a nice thick sock.
I sized up in my Charmoz as I'm not much of a scrambler, so my thick sock made me choose a size bigger. My feet were toasty on the summits in the cold depths of a Lake District deep freeze as a result.