hos111340845wrote a review of Arc'teryx Acrux AR GTX Mountaineering Boot on April 25, 2018
Familiarity: I've used it once or twice and have initial impressions
Fit: Runs small
I'm confirming all the positive aspects of this boot. However, this is the first rigid double boot I've owned. Many reviewers mentioned it is narrow; or rather fits a narrower foot. My foot is slightly narrow, so based on reviews, I bought a full size larger (11.5) than street shoe (10.5) and this worked excellent. It is still very snug on the side, gives ample room for toes, and room for an extra thick sock, or 2 pairs of medium weight socks. I can cinch the laces, and Velcro strap and have secure heel without movement.
I bought these 2 weeks before two ascents in Ecuador: Cayambe - 18,900 and Chimborazo --20,200; 6 hour and 8 hour ascents. Excellent control and moderate weight of the boots was appreciated. I wore liner and one medium weight sock. No cold feet at all.
It matches a 12 point Cassin Crampon (Alpinist Pro) very nice for an aggressive response. Love this combination.
The zip fastener of the built in gaiter probably contributed to warmth. It was nice feature; so I didn't need to use my external gaiters during the mixed snow/rock/mud conditions, until getting up onto glacier when I put on crampons. I liked.
I tried and compared to Scarpa Phantom 6000, and chose ArcTeryx after wearing extensively indoors. I liked the slight extra length, but tight side fit of the Acrux.