Summary: I use this hood on the EF 85mm f/1.8 USM. It is a fine hood. The lens is not particularly prone to flare, I use the hood more to protect the large front element of the lens. It's pretty light and plasticky, but this makes me confident that if I hit it hard enough on something, the hood would break, and not rip the front of my lens off, which is a comfort.
Summary: Does exactly what it is designed to do. Works well with the lenses it fits. I always buy a hood when I purchase a new lens. It provides protection, as well as preventing stray light. A worthwhile investment.
Summary: This hood simply clips onto the lens and with a squeeze of two buttons comes right off. I didn't give it all 5 stars because it feels like it could fall off at any moment, but still hasn't so it must be designed that way. As far as doing it's job, it does just that. It keeps unwanted light out and doesn't get in the way of my on camera flash. All in all I would buy again.