I never bothered to get one. When I shooting and go to portrait orientation the right side of the camera goes down and my finger never leaves the shutter release. I don't understand people who have to "twist around" to do this.
My camera doesn't live in a bag. It goes around my neck and I don't need more weight.
It takes me about ten seconds to switch to a new battery in my K10D and I always have a charged battery with me.
If it feels good and you like it or if it looks good and you like it, that's fine. Functionally, it adds nothing for me.