I have a Joe Rocket jacket and love it. I have not been down in it (knock on wood), but bought it after seeing someone's who had. It showed minor fraying, but was not worn through (sorry, I can't remember the speed, but it was not a parking lot "whoopsie").
Anyway, I wouldn't ride nearly as much during the summer without it. You notice it when you are stopped, but once you get going the air flow keeps you comfortable.
All the above being said, it is not even close to wearing a former cow for protection! :bike: