I've got a grip from Link-Delight, and it came with all the features the Cnon one does, and it cost me around $80 Cdn. shipped with batteries.
The only thing I can gripe about is that the wheel is not as tight as the one on the camera, but that is just a feel thing. It works perfectly.
I have had a glitch a couple times when I could not adjust the aperature with the camera button, but I think the problem was that I unknowingly nudged the wheel on the grip and it was half way between clicks, so once I turned it all was good!
Hope this helps.
Cheers