Not that I have any experience at high altitude.....but....
I used to work at a gear shop and trying on the Spantik one day, the lace broke. I dunno but if that happened high on the route, you would not be a happy camper.
From Sportiva, I would consider looking at the Baruntse instead.
But of course, it all comes down to what fits your foot the best. Go to a store that carries a few and try them all on.
