I got one a few months back, but never really used it because of one major annoyance. The L bracket mount makes it next to impossible to use the camera in portrait mode, i.e. with the battery grip attached. I see that they have now changed the mount to a knob type design (
http://www.robertsdonovan.com/?p=986). Still, I believe this will get in the way if you are using the camera with a vertical grip.
One more thing is that storing the camera with the strap attached is pretty much impossible. The camera won't sit flat on a table, neither will it fit properly into my bag (connecting bracket is an unwanted protuberance)
Other than this, I think it's a very good product. Ergonomic (to wear and to use in landscape mode) and excellent build quality. Just don't get it if you are a frequent portrait shooter like me.
Cheers,
Keith