They are the only Canon grips for the 40D - there are other 3rd party version available on ebay etc.
I just bought one of these and although I haven't compared it with an official grip, I'm very impressed with it. It adds a lot more functionality that the official one doesn't.
I have the BG-E2n for my 40D, and I think the only difference between the two is some weather sealing...IE some strips of rubber...around the battery compartment. Got a feeling there was another difference too, but cant think what it is off the top of my head. It is nothing major though.
Garry, is it easy to use?
im a bit of a wimp when it comes to this one, im a bit unsure of spending hundreds of pounds on a camera and glass to go with it, then to put the cheapest grip money can buy onto it ..... would the camera still be covered under warrenty with a third party grip attached.....
That grip looks fantastic!