Anyone had a chance to use either of these pants? I'm looking for a do-it-all pant for ice/alpine climbing as well as ski touring. Not sure if the Castor pants would be breathable enough. If you'd owned these pants, let me know what you think. Thanks.

The Champ pants are quite breathable.
I've done alpine climbing and skiing in them.
They are durable and comfortable, but I have sometimes wished that they were slightly more windproof.

I recently purchased a Mammut Laser Jacket, which is made of the same material as the Castor pants. I've only had it out a couple of times but, so far, I'm very pleased. It breathes well and it keeps the wind and water out.

The Laser jacket is not made of the same material as the Castor. A quick overview:

Castor: Scholler face fabric, laminated (polyurethane) interior. Pretty much a fully waterproof (except that PU sucks for waterproofing) pant and it's not very breathable. Windproof (again - PU sucks though)

Champ: Scholler. Breathable, somewhat water resistant, no laminate, super strechy and mid-warmth. Great for going uphill, though I'm a bit nervous about them in extreme cold. I'll be using mine on Denali this year - we'll see.

Laser: Scholler, but thicker than the Champ. No laminate. Warm but really breathable.

To me the Castor is a ski pant (like resort skiing) and the Champ is a climbing/touring pant. The only advantage of the Castor is the zip on the bottom - it fully unzips with a velcro snow-guard. The champ has a zip as well but it doesn't fully unzip ... it's gusseted.

There. Now go get a math degree to figure out Mammut's sizing chart.

I own both the champ pants and laser jacket, I have worn them in the Adirondacks on mornings when it was -15 F and had no problem staying warm, and I wear light layers underneath. They are not very windproof, but I sweat a lot so that is actually a blessing for me. They are both very comfortable and you can maneuver very nicely in them. All in all I am very happy with them, although I cannot stand the opposite side zipper on the jacket, makes me feel like I am wearing ladies clothes.

I'm sure this will branch out, so I'll help..I use the Mountain Hardwear Vertex pant, but I believe they are out of circulation. I actually also use the Marmot Scree pant for ice and alpine. Low cost ($100), super stretchy. Throw some HW powerstrech underneath and good to go.

I own the castor pants and have taken them out on a few tours as well as an ice route. Due to the Schoeller stretch membrane (WB-formula) these pants don't breathe quite as well but I have found the side vent zips work great. The built-in gaiters fit very well over a ski boot but are a bit baggy over a mountaineering boot. The overall fit is excellent and having a waterproof pant that stretches is an amazing accomplishment in the field of technical garments. Although after close inspection it does not appear to have taped seams which would mean the pant isn't completely waterproof. Any thoughts on this?
http://www.schoeller-textiles.com/pdf/stretch_wbformula_e.pd>>>>>

I've used the Champ pants since they first appeared on the scene. The Euro sizing numbers are hard to figure but the fit chart worked for me. My normal pant size is 31 X 31. I wear Mammut Champs in size 24. If you have longer legs you'd wear a 48. I don't think the waist sizes are tight on the chart. They are totally awesome pants. I've used them with wool long johns in all winter conditions here in Wyoming. They also work great for summer alpine conditions without long johns. Sometimes if its way below zero and the wind is howling you'll need hard shell but for 99% of conditions you won't find a better pant for backcountry skiing or alpine climbing.

You are forgetting one other style pant that Mammut make that falls inbetween these two and that IMO is the best all-round pant that Mammut make and that is the Courmyier (sp) pant.

I've been using the Champ pant for years as both a ski and ice climbing pant. It's a great pant. It's been my observation that the current fit is a bit baggier below the knee than has been the case in past years. Sometimes I accidently catch the fabric in my crampon points. The Scholler 400 material that it is made from is very breathable and is fairly wind-proof but there are days in RMNP when I want something abit more windproof and waterproof.

The Castor pant is great for skiing and general mountaineering. The fabric is more windproof and waterproof that the Champ pant and the built-in gaiters are a nice touch. The pant's fit is abit restrictive for athletic ice climbing and the overall weight is more noticeable than either the Courmyier or Champ pant. This is a good choice if you do more skiing than climbing. It is less breathable than the other two pants.

The Courmyier pant is light, very windproof, and water-repellent enough and the fit is very trim and perfect for climbing. This is a pant I would use year-round in RMNP. It's abit too much (a little heavy for a summer pant) maybe in the summer but it will work equally well as a rock climbing pant on Long's as well as for skiing or ice climbing any other time of the year. When the temps drop I just layer heavier underneath it, but again, the fit can't be beat and it has all the pockets that I need. Check it out.

Just a follow-up, I spoke with a Mammut rep and confirmed that the seams on the Castor Pant are indeed TAPED, didn't want to cause any confusion. I can highly recommend these!

Castor Pants, I get more Tang than an astronaut!