I know a lot has been said on the capability of these boots for Denali. TAT just posted a pic of Steve House unloading on the glacier wearing Spantiks, Good enough for Steve.....?

Lots of people use them. If you get cold feet use the Olympas mons or Millet or equivalent. If you are going late season you should be fine. No they are not as warm as the big 8000 meter type boots. I use Kayland 8000 because I dont like cold feet and they are really warm. I used to use Invernos with thermofit liners which were also fine but the kaylands are warmer and more comfortable.

Had them twice on Denali, once with over boots. Performed well on Vinson. May not trust them for Everest though!

When you say late season, when exactly do you mean?

I'm starting on June 5th. My feet never got cold on Aconcagua with the Spantiks.

There are lots of threads about this very subject and there doesn't seem to be a great consensus. Everyone seems to say they are sufficient but bring overboots anyway, just in case.

I had Spantiks on Denali and was able to summit with them, without over-boots. People who do not keep a good pace and whose feet get cold easily (mine usually do get cold easily though) might want over boots.

Ok, I summitted Denali as well without over lots boots using spantiks after worrying a lot about this issue.

I climbed the mountain at the very beginning of June 2013 in only 9 days. I had very good weather most days and found the mountain very warm overall.

I know you should be prepared for anything on denali, but also be prepared for it to be warm and sunny. I never wore long underwear the entire trip. I would have sweated my butt off.

Because it is light pretty much 24/7 up high I never felt the need to go out early when it was cold. Summit day started for me at 10 Am when it was already warm. I was on the summit by 4 pm and back by 6 pm. I was never cold, not even remotely.

I should add, I was not in a guided group but in a two man team. Therefore I had plenty if say in when we did things. If you are slower and gonna be climbing at the whim of a guide it might be good to have the over boots. If you can afford 6k for a guide then you can afford over boots. I'm poor though

These boots are definitely good enough for me. Worn them in -45 F on Denali. early spring (April) in the St. Elias range and on different 7000 meter summit attempts in Pamir. Would certainly use them on Everest as well...if I would ever go there, which I absolutely wont!

I like my Spantiks just fine. But, am likely going to move to the Mons or similar for my trip to Everest.