Gilian L.wrote a review of Outdoor Research Alti Mitten - Men's on October 15, 2014
Familiarity: I've used it several times
Not recommended for high altitude...
These are surprisingly thin when compared to BD Absolute Mitts which were much 'puffier' and filled up (side-by-side comparison).
Maybe it is my hands/fingers but I could not keep my hands warm in these so called expedition level gloves. Sadly my hand warmer packs also failed to activate and my fingers were painfully freezing. The outside temp was in the vicinity of -35C so it was pretty damn cold on summit night.
Given my experience in seriously cold temps, I would go with a more insulated glove that is puffier. Down suits are very puffy to trap and heat the air from the body, and that is what is needed on the hands. Alti Mitts are way too thin in insulation and the Primaloft insulation by itself does not trap enough warm air (need some filler such as down).
Even wearing an extra thick glove liner didn't help.
I'll be looking for a new pair of high altitude puffy and thick gloves...probably the TNF Himalayan or BD Absolute Mitt.