Just got one of these, and the fit and quality are typical of arcteryx (better than pretty much anyone else). The material is quite light, but provides a fair bit of warmth. Likely to be a bit too hot if you are really working. Does not bind under other jackets. beware, the size chart is a bit misleading, as I would personally go for the next larger size than what is recommended, especially if you are tall. I have a 38 chest, so I ordered the small, which felt like it was painted on and did not even cover my belly button.

I like this heavier base layer for the colder days, or when I'm not going to be working up too much of a sweat.

I love this top layer from Arcteryx. It is super comfortable, warm and light and has the great Arcteryx quality. I use it as a base layer or as a mid layer depending on the activity planned and the weather and temperature. Great service as always.

I have this top in Black. It is a great piece. I generally use it as a layering piece for skiing. The fabric feels great against the skin, soft and comfortable. It also looks great on its own. I have received several compliments on it when wearing it after skiing or hiking.
The single pocket is great it is a great size and doesn't sag. I often carry my cell phone in the chest pocket.

This has got to be the softest base layer I've owned for skiing. It's so comfortable I don't even want to take it off after skiing. I love the chest zip pocket, don't think I've ever used it, but I love how it looks.

I have used the Rho alpine and xc skiing as well as on many hiking trips with temps ranging from around 50 degrees (F) down to 0 degrees (at the base of the mountain). This layer is amazing in the range of temperatures that it covers, I rarely overheat and yet it seems to keep me warm when the temperature drops. It is very comfortable and dries quickly, I have an average build (5'11" around 175 lbs) and it is snug on me, but very comfortable (the way a base layer should be). I am planning on getting a couple more of these and making this my standard base, it is a little pricey, but well worth it.

Top-notch quality, and perfect sizing for this product. I haven't tested this with layering as of yet, but it does feel good on it's own. I wouldn't wear this on it's own casually, as it does fit tight, and looks rather strange. The sleeves are a bit long, and I'm not a fan of the zip-neck (too tight for people with thicker necks). Overall, this is of better quality than a similarly advertised underarmor product. I'll be using this in the winter.

and have been thrilled with the tops...in my review of the bottoms I say how I prefer the powerstretch but I really like these on top as a first layer. Combined with a thicker wool sweater these are a part of a super versatile layering system that adjusts to different temperatures well

Bought two now. One for husband, one for Dad. Soft, VERY warm, stylish, and light/compact. Does well in washer/dryer. Have been happy with all Arcteryx gear. Although expensive... worth every penny. Especially when living in cold northern climates

Great for layering. Have yet to use it as a single layer. Generally will add an Icebreaker piece underneath the hardshell on colder days when skiing the backcountry.

It would be nice to see some reviews on the size and fit you purchased. What is your height/ weight and what size do you wear in other brands? ie MH, TNF? Thanks.

I returned the product. It is a very tight fit. It wasn't something that I could wear in a casual setting. I do wear tighter clothing that most North Americans, and I still thought it was too uncomfortable for social situations. The material quality was disappointing. I am sure that it will be okay if you are just looking for a skiing base layer, but I don't consider it a multipurpose product.

Nice. Very very nice. Good quality.

The size runs a bit small for me, I ordered a second shirt xxl, I like lose fitting shirts, other than that a bit pricey but like it.

This shirt was clearly designed to be a base layer as it fits skin tight (I'm a 5'6 @ 120 lbs and bought size small). I ended up returning it, because I was expecting to be able to wear it as a normal shirt around town, which clearly I could not.

I have two Rho LTs and Those always give me a lot of
softness and warmth.
In many cases I wear size M, but I should buy size L, so I hope that backcountry.com gives a more precise sizing chart for this cloth. And color in picture of website is much more brighter than that of real thing.
Except these, this is one of the best layering wear.

Arc'teryx is great. Men's small size is a perfect fit for me (female small-medium). It was a great baselayer for a week in backcountry snow, where sweating profusely was not an issue, so I don't know how this shirt wicks moisture, but I stayed dry and warm.

I just used my Rho LT for for the first time on the Fort Bliss 10k run in 40 degree weather. It did a great job keeping me warm while wicking sweat extremely well. However, you might need a jacket if it is much colder or windy. As for the sizing, I'm 6'1" and 210 lbs, and the large I ordered fits perfectly. For me, it's a perfect athletic baselayer...plus, the pocket is extremely useful for carrying a key and/or ID.

Awesome! Feels very soft next to my skin, sleeve length is perfect for a guy who is 5"8 and ordered large size Rho. Attention! You might want to size up with this item. Medium sized Rho was a bit too tight for me in shoulders so I had to exchange for a large one. I also think that an extra large would fit me almost fine although it probably would not have snug fit.