love them, worth the cost
In short, I'm pretty skeptical of a $20 pair of underwear, but I want to wear them all the time, so it's not a high cost per wear over the lifetime of the panties. To me, they are worth it.
I decided, daringly, to order three pairs of these Barely Bikinis without trying them before. They were on sale, and I already loved the two pairs of the fuller-coverage Patagonia Active Briefs I had. They had rapidly become the first ones I put on whenever I had the choice.
The Barely Bikinis are better in some ways, and I'm glad I went ahead and got all three colors. They are as soft as the Active Briefs, but I don't have to worry about wearing them with low cut jeans. The cut is very flattering, they stay in place, they are breathable and comfortable. There isn't even a tag to annoy or irritate.
Other observations: they are definitely a thinner fabric than the Active Briefs (a plus in the humidity, maybe a minus in cold weather). Honestly, I haven't tried them in potential panty-line situations, so I can't comment on that.
Incidentally, I also ordered the Mountain Hardwear Advance Lightweight Brief (those sales really sucked me in). They are fine and I like them, but they are the size of a swimsuit bottom.