Just wondering what type of mountaineering boots people have used and would recommend for Orizaba and/or Izta.

Just incase you didn't know, there is a search feature at the top right of all SP pages that allows you to search the forums. There are a few previous topics about boots for the Mexico Volcanoes.

http://www.summitpost.org/phpBB2/viewtopic.php?t=33674&highlight=boots+orizaba

http://www.summitpost.org/phpBB2/viewtopic.php?t=39825&highlight=boots+orizaba

http://www.summitpost.org/phpBB2/viewtopic.php?t=23210&highlight=boots+orizaba

I myself used Koflach Arctis Expe's. Hope that helps!
-Luke

When I did Orizaba I used my La Sportiva K3 boots (I believe now discontinued and I now use the Nepal Tops) with gaiters. I think high end leather mountaineering boots with gaiters are more than sufficient and my preference because I think they are more comfortable. My partner used a plastic boot, I believe the Inverno, and was more than warm. As long as you don't show up with tennis shoes or day hikers you're in good shape either way.

FYI
We hooked up with a solo climber from Ecuador on that trip that basically climbed it with old, warm out day hiking boots with crampons more or less taped on. We did have to gets his boots off on the summit and rewarm his feet, but even with that set up he summited and got down with all his toes...I wouldn't recommend it though.

I would use some light boots that are crampon compatible. When we did Izta and Orizaba, I wore Sportiva Makalus, but would go for Trango S Evos or something like that.

That said, we had really good weather. Here's my trip report :
http://www.splattski.com/2008/mexico/index.html

Do you think Sportiva Karakorams, a three-season mountaineering boot, would be too light for Orizaba?

LS Karakorums look like a good boot.

The thing about mountains is that every day is different. One day the snow is soft, the next it could be super-hard ice. One day it's warm with no wind and firm snow, the next day is cold, windy, deep new snow and miserable.

It would be easier and faster in running shoes. But if it's cold, running shoes might get you frostbite. Or you can play it safe and wear double plastics. But they would be heavy and slow.

Somewhere between those mentioned, from leather dress shoes to plastics, would be good for most days. So you have to interpret our experiences and think about your own. Then decide how much you want to risk.

It wasn't that cold when I climbed Orizaba probably around 30F, but I used Kayland Super Ice (a discontinued model). I've used these boots in colder temps and they have always kept my feet warm and comfortable.

I did Itza and Orizaba in early January this year. I bought a pair of La Sportiva makalus but they were too small. I ended up wearing my old pair of half shank Montrails with strap on crampons. My feet got a bit cold so I'd definitely go with more boot in the future. If you have interest in these Makalus, they are size 42 and brand new. They'd probably be a good choice weather you're interested in my pair or not...especially if you want to use automatic crampons.

La Sportiva Prime in November, cozy warm.

I wore my Lowa Mountain Expert GTX. Climbed in February. Dry, warm, blah blah.

Have fun.