Haven't taken these on a serious climb yet but so far I'm really impressed. They're so light. Warmer than you think they will be. The construction is really impressive. Not a single flaw. They are fairly stiff, but the rockered sole does help for walking. I took them on a 5.5 mi. snowshoe after 15" of snow. Feet stayed completely dry. I did have light gaiters on but some of the lace portion of the boot was exposed. I wouldn't recommend them for a 10k+ winter climb but I feel very confident they will be great 3 season boots. Probably not warm enough for most summit days on Rainier but they would probably suffice for almost any other summit in the lower 48 June-Sept. Looking forward to strapping some crampons on them this Spring/Summer!!
They run slightly small. I would not size up a full size. Maybe a half. I bought these to replace Salewa Alp Trainers and Salewa Rapaces. Both were 44's. These 44's are slighter more narrow. That being said I have moderately wide feet and I can wear these. They fit me better than La Sportivas do. When you slide them on you feel the effects of the 3D Laser design, the inner boot molds so well to your foot. I did have a hot spot on the left heel but I typically do with most new boots. Athletic tape kept it from blistering.

Just took these for a 20 mile spin with a 50lb pack. First impression was good. Very light, great support for the weight, and great build quality.
The initial few wears around the house left me with the impression that fit was pretty true to size, but BE WARNED! What I couldn't tell until I got some miles on them was that the narrow, almost pointed toe box caused the boot to put a good deal of pressure on my smallest toes on any kind of sustained down hill. I would advise folks with average width feet to consider sizing a half size up, and those with wide feet going a whole size up or to look elsewhere.

I'm getting a half size larger pair on the way ASAP and will update my review when I get some miles on those.

These are my new favorite boot for pretty much everything that isn't cold temp, ice climbing, or pure winter mountaineering.

The first thing you will notice when you put these boots on is the fit - they are not only comfortable, but the heel feels solid, and the toe box is roomy, but not oversized.

The other thing i have noticed is how low profile they appear on foot. They are slim - and coupled with the weight of just 1lb, they are super agile.

They are stiff where i want them - right under the mid sole - but have a rocker to them that makes hiking feel natural.

They are essentially a technical hiking boot, with the stability and feel of a 3 season technical mountaineering boot. They take a semi-auto crampon beautifully and have a very burly vibram outsole for their weight class.

If you are looking for a boot that is more than a hiker - where you will spend some time crossing snow fields, or meandering through some boulder fields - especially with a heavier pack on, these are a killer boot.
I am a 9.5 street shoe and these were perfect right at the 9.5. so True to Size.

I am definitely planning a cascades trip to climb a volcano now that i know what these boots are about.

And did i mention how LIGHT they feel?