I had it with my first camera when the 400d first came out.
It changes the feel of the camera a lot, and besides stopping a few scratches, i'm not sure what else it would have protected. I also found the smaller buttons not very responsive. I'm not sure how the wheels would go on the 5d's.
On another camera protection product.. what are everyone's thoughts on Lens Coats?
I haven't used one on any of my Canon gear, but i use them on the 200-400 Nikkor and 600m nikkor lenses that i use for work.
I recently shot in the Himalayas in Kashmir, and wanted some thermal protection for my 70-200is2 and the only colours i could get where army colours, i didn't really want to look like i had a weapon there in these volatile times so i went without.
besides birdwatchers, is there any need for Lenscoats?