I was notified on 6/18 that the BG-E11 I ordered from B&H was on 3/30 was on its way to me. I've been waiting anxiously...my battery packs are charged and ready to go. If the experience is anything like that with the grip for the 7D, I will never remove it from the Mark III body.
I shot landscape all afternoon with it on. Felt like a 1D body. I love it. Most of the time though, it's on a tripod, but when you carry the tripod around you can feel the weight. It's cool.