I have used these boots most extensively on vertical ice, but also for some winter mountaineering. As far as plastic boots go, I think these guys are about as good as it gets. They edge very well. They are very true to size with Asolo's other hiking boots. I went up a size to accommodate two socks. The boots aren't overly bulky like Koflachs (which I used for a three month expedition in Patagonia), but are still plenty warm due to the great liner. I've been ice climbing in Minnesota at -12F, standing in ankle deep snow the whole day, and my feet (with two socks) were doing fine. The stiffness makes it great for frontpointing and vertical ice, and the dual laceups allow you to really fine tune the fit. They are fine for long approaches too, as are any boot, you just need to learn how to walk in them. Approaching in stiff mountain boots takes a different form than flexible hiking boots. Walk a bit duck-footed, lift with your hip flexors, and try to step flat-footed and you'll be fine.
"Super comfortable, true to size (comparable to Asolo's 3/4 shank hiking line)"
This review is based on the use of these boots in South East Alaska's climate. (Temps ranging from 0 deg F to 40 deg F, try the 8000's for colder temps). Liners broke in after one climb (caused blisters on my arches, but none since first use). Liners are great; comfy, and super waterproof. They have a grippy sole for walking around camp or leaving the snowy, muddy shell outside a restaurant. Sole offers phenomenal edging for scrambling and low grade rock climbing. They're great for ice climbing. They work seamlessly with my Voile splitboard when combined with the automatic style mountain bindings. Sweet for skinning; wrench on both sets of laces for a solid downhill run.
These are much nicer than the Scarpa invernos because they have a velcro inner boot. Much easier to get on and off, plus no inner lace keeper to bang up your shin. I have made two Rainier summits and a Denali summit with these boots. I like them, but you will need to buy a foot bed and custom molded liner for any serious expedition use or for sustained long ice climbs.
Okay - so I took these boots out for the first time this past weekend to get them ready for a Rainier summit (hopefully) in July. The boots were fantastic. Super warm, and I only got 1 (really minor) blister after an 8 mile hike.The boot is nice and I got several compliments from other folks hiking the trail. The only bad part about the boot is that the foot pads aren't very nice. I think I'll have to get some superfeet insoles (hopefully from Moosejaw!).