I use these for ice climbing and any snow riding. They are super warm and incredibly comfortable. I should have gotten the boot length, but they still work perfectly. The side pocket is perfect for a key like Arcteryx suggests, but i throw my clif shot in there so it doesn't get to cold and frozen. Super accessible with any side vent ski pant.

These Rho LTW are great. I wear them with my soft shell pants. They regulate my temperature very well - warm and dry, not sweaty and hot. I have had issues with wool due to sensitive skin. No issue with these bottoms. Best buy in my opinion.

Very nicely detailed - like all of Arc'teryx products - but let down by a very odd cut. The legs are extraordinarily long relative to the waist.

Got one pair this winter. They are soft and fits very well, medium, and I am 5'11, 180 lbs, 33 waist. However, they are LONG, 2-3 inches too long, but far from that they are great. Also got their LTW Shirt, but took size large, don't like when it is to tight. Fits great. Not as soft as the bottoms.

I wore these five days skiing at Alta in 20 to 35 degree weather under North Face Pants. They kept me dry and comfortable. The boot cut is perfect. They do not get bunched up in ski socks and boots.

I own two pairs of these... they fit me perfectly (I generally find that Arcteryx products fit me better that most of the other major manufacturers). I wear them under soft shell pants while b/c skiing in the Canadian Rockies from fall through spring. They regulate my body temperature very well and the merino wool is great for the no stink factor on multi day trips. I have two years of use from the first pair and no signs of wear.

These undies are great. They wick well and it takes a lot to make them stinky. I am a 34" waist and a large is a tad bit big on me but I prefer my base layer to be tight fitting. If you don't mind a baggier base layer then go with your usual sizing. The pocket on the thigh is pretty useless... When are you ever going to store something under all of your other layers? It would be a massive pain to actually get to if you needed to. Only bills and coins really fit in it. I'm convinced the pocket's main purposes are to provide a spot for Arc'teryx to slap on their logo and make the garment stand out from other wool underwear lacking such a pocket.

These wool bottoms are great. They're not itchy. They wick moisture. And they won't stink after you sweat in them. My only complaint is that they're too big at the bottom and there's excess material below my calf. I love the covert pocket.

Sigh, I think the good people at Arc'Teryx made these bottoms for the starting lineup of the Vancouver Grizzlies. They arrived way too long, even in size small. I had to return them for the Rho Bootcut pair, and even those reach all the way to my ankles. I am fired up about the Rho bottoms though, wool is def the best way to go for insulation.

These make for a great base layer, you can't beat merino wool with a touch of lycra. I think these are bit higher quality than the Icebreaker. They hold there shape better after a few days of continuous wear compared to the Icebreaker.

Being from Australia and having a kiwi wife makes us big fans of Icebreaker and between us we have about 20 pieces. This time we thought we´d try Acrteryx Merino and we were pleasently surprised. The build quality is typically Arcteryx, second to none and these tights seem a little thicker than my icebreakers. We both stayed warm in Denali's backcountry in mid September. The tops run a little small so DEFINATELY go a size up in tops.
Thumbs up all round

Great baselayer. It keeps you warm and keeps out of your way. The one benefit I always notice with Arc'teryx is that their products work without question, and they look really good doing it! Size down though, I'm a medium and needed a small. They also run long, so keep in mind that they offer the boot cut.

I really like these. They aren't bulky. They keep me warm, but not too.
They are comfortable to the point that I forget I have them on. I don't mind the wool, but if you are easily bothered by wool the Rho LT are just as great. Also, you will want to use a 'delicate' detergent for the wool, but you can go long time between washings.