Are radial contextual menus better than vertical list menus?

I've read suggestions that contextual menu items be arranged in a circle around the mouse cursor when the menu is activated, since Fitz's Law suggests that each target would be easier to hit.

However, I've never seen this in practice. (I can think of a few simple reasons: text is hard to fit in the space afforded by a wedge-shaped target, it's not a standard pattern and is perceived to be too confusing, etc.)

Are the potential benefits just not worth the trade-off? Are there examples that work that I'm unaware of?