Got this on SAC for $16, which was a steal considering how awesome this jacket is. I have worn it in rain, light snow, and 60 MPH gusts throughout the Sierra and Red Rock, and tested the water proofing in the shower. You will stay dry, and it cuts the bite from the wind. It is very light, and with the included stuff sack it packs up very tight, smaller than two soda cans side by side. It's my main shell backpacking shell during the warmer months, and I love it. If the forecast calls for some serious weather, I would pack something more substantial, but as an "oh-crap, its raining" piece, it can't be beat.
Bottom Line: Need a summer backpacking rainjacket? buy it