They both have their appropriate place, I would say. I own both of the DVDs and learned quite a bit from the first one, and focused more on advanced techniques in the second.
Murray Carter prefers using a sharpening medium that is comparable to the hardness of the steel itself. I'm sure the technique he teaches could be used on DMT stones, but the idea that you need something hard to sharpen steel - and therefore diamonds are the best option, isn't necessarily true.