Planning on getting a grip for my 6D eventually. However I had a third party (Zeikos) grip on my 7D when I bought it. One of my batteries (both Canon) would have a hard time registering. Also the shutter button on the grip would decide when it wanted to work. Eventually the wheel that tightens and loosens the grip broke so the grip was literally stuck on my camera. Luckily I managed to get it off without damaging the 7D. I've heard stories of people having to send it into Canon and having it cost more than anyone wants to pay. With that said, I'm only using genuine Canon grips from now on. I bought a genuine for my 7D and haven't had any issues since.