I have not tested it in the rain but as far as light weight vented jacket it has been awesome ! I have rode with it on a few upper 40 degree spring days with no problem when I started heating up I just opened a vent or two to keep my body temperature just right.
Got a post-season deal on rain protection I've been putting off for years. This Showers Pass jacket keeps the rain out while providing plenty of ventilation - even in mild temperatures where I would have expected uncomfortable sweat buildup.
Well made, thoughtful design. More visibility is the only design feature I wish it had. But then, that would reduce the product's Metro cred.