Need help with Michael Jackson This Is It DVD!!!!!!!!!!!?

I can't decide which Michael Jackson This Is It DVD to buy. I either want the 1 disc one from Walmart or 2 disc one from walmart. What I can't figure out is: does the 2 disc one have exclusive Michael Jackson rehearsals and footage or does it just have stuff about the backup signers and dancers? I appreciate all of the help that I can get. Thanks!