Haven't tried this for hiking, but for running, I really like the Moving Comfort Juno bra - great for wicking and drying quickly and the best bra I've worn for minimizing chaffing on long runs, since it doesn't hold a lot of moisture against the skin. Also a great fit (minimal boob smashing). Downside for hiking is that it's more supportive than I need for a hike (definitely not an UL bra!). Moving Comfort does have a wide variety of options though, and the website is pretty helpful in figuring out what bras might work best for activity and body type.
For comfort, I like the Patagonia Capilene Mesh bra so far, although I haven't tested it on a backpacking trip yet, so not sure about wicking and moisture performance.
Thanks for the thread - I'm still searching for my perfect hiking bra for comfort and wicking too. Looking forward to hearing other suggestions!