Comfortable
Bought these briefs a week ago. Tested last weekend on a sailing trip. Very comfortable and nice. Keeps me warm, at the same time they are very breathable. Great addition to Capilene bottoms.

Excellent
Very comfortable, good fit, lightweight, and fast drying. Nice looking too. Take up almost no space and minimal weight in a backpack so go ahead and bring a spare pair.

Briefs for surfing
I purchased the Patagonia active briefs to wear under board shorts and a wet suit while surfing. Sometimes the board shorts will rub in the wrong places after a long time in the water but the active brief guards against that. They were great!

Like wearing nothing at all.
I originally bought a pair of patagonia briefs that were advertised as capilene. I got them on sale so the price was right. They have been so comfortable that I have been looking to buy another pair but couldn't find them in capilene. I decided to take a chance on these because it appears they no longer make them in capilene. These, however, were pretty close to capilene in composition and are designed the same. I am happy to say they are just as comfortable and even a bit lighter in weight. I never thought I would purchase underwear at such a high price, but they are so comfortable when hiking, biking, climbing or skating. Closest thing to wearing nothing at all and won't contribute to hypothermia like cotton ones might. These may run small unless you like your underwear tight.

Impressive underwear
I was highly impressed by the complete absence of any seams on these briefs, very comfortable to wear, a great job on absorbing and wicking moisture and my girlfriend likes them as well. Cannot go wrong with these. Also notable is patagonia's effort to use recycled materials. These are a bit pricey but if they are durable it will be a great buy.