A lot of times, I actually buy both. But Megadeth is not a band that I would ever sit down and watch a live DVD. I would, however, be more apt to listen to the CD in the car, on my iPod, etc..
My thinking, or hope, is that the CtE songs will have a bit more life and feel fuller than the studio versions.
My other problem is that compared with RiP Live, this repeats She Wolf, Trust, and Peace Sells, not to mention Symphony Of Destruction, Holy Wars, and Hangar 18.