While the RHO LT Zip was the most expensive of the base layers we tested, the top looked and performed at the top of its class.
I have a longer torso, very long arms, and broad shoulders, which means that often times, base layers are either too short in the torso, the sleeves, or both. For activities with extensive stretching, twisting, bending, etc. (i.e. almost everything!) this becomes a major problem. I was so excited, than, the first time I put on the RHO LT Zip and found it to be snug and sleek, without pulling or riding up around the waist. And Hallelujah! Arms that are long enough! The true test would be washing the top, and when washed, the material held up without pilling or twisting, and there was virtually no shrinkage. Over time, the RHO has kept its fit and proved to be highly durable while maintaining softness.
One morning, I selected this base layer for a brisk, uphill hike in cooler, drizzly conditions — the conundrum of a situation when you are both hot and cold simultaneously. The top performed beautifully! Excellent breathability meant that it was practically dry when I reached the top, and didn't make me cold on the way back down. It was thick enough to keep out the drizzle, but the arms were easy to push up and the zip neck allowed me to cool off when needed. I used the zip pocket on the upper arm to hold my keys, and it was tight enough to keep them from sagging or jingling, but not so fitted that I felt them digging into my arm. It is attention to details like this that make a base layer great.
Afterward, I kept the top on for a while and it was super comfortable, rather than stinky or soggy. Like the Under Armour Base 2.0, this is a base layer that can be worn long after your exercise stops. While a bit heavier and slower to dry than the Base 2.0, it is far warmer.
I only have two real complaints about this baselayer, and even still they do not outweigh the positives. For one thing, while it is a top for all occasions, it is not the most versatile when it comes to layering. The zipper at the neck, and the mock neck itself, might discourage you from wearing it under other tops (excepting your outermost jacket). This is added to by the fact that the whole idea of a pocket on the sleeve is so that it is readily accessible. However, the top is also so fitted that I was uncomfortable wearing anything other than a sports bra or the thinnest tank under it.
Secondly is the price tag. Simply put, $109 is not a small sum to drop on any piece of clothing. While it was definitely one of the best base layers we tested, there are others that performed as well, or close to it, for far less of a cost.
Use this baselayer for all your athletic endeavors, excepting the highest end aerobic activities or warm weather sports. The fitted design and super stretchy fabric makes it ideal as far as freedom of movement goes. The seams are strong, and the fabric can hold its own against the outdoors and the washing machine. This top is good for skiing and winter sports, running, horseback riding, camping, climbing, backpacking, and hiking, just to name a few.
For an extra $10, you can buy the RHO LTW, which is the same top, but made of MAPP Merino Wool. There is also a women's version of the LT Zip, called the Arc'teryx RHO LT Zip - Womens, which wins our Top Pick Award.