Currently when I deadlift I use a double pronated grip for as long as
I can before switching to an alternate grip for my work sets.
I then switch which hands are pronated/supinated so I don't develop imbalances.

My question is is this the best grip to use for strengthening?
I have some experience using a hook grip too, is that a better bet?

I've been inspired to try it after seeing this 836lb deadlift using a hook grip:

http://youtube.com/watch?v=f8HQOoJvQws
In the video comments he states: "I use the hook grip cause its better for the biceps, the back and to avoid great tensions in my back, my shoulders and my neck."

I'm not sure if his reasons are true, but with a lift that strong he's obviously doing something right.
What do you guys think?