I wear one for commuting because it keeps you dry and doesn't make you sweat as much as a jacket. IMO the downsides are:
It's wind sensitive - best suited to riding at a slow pace
If heavy duty, it's bulkier than a jacket when off
The hood blocks your lateral vision. Better to cut the hood off and wear a rain hat (or a helmet cover if you wear a helmet)
I prefer a bright yellow one for added visibility. And no, I've never been yelled at.