Having only briefly glanced through the previews, my initial reaction is that no, I won't be using them.
I feel that, if anything, they confuse and obfuscate the rules rather than clarify or simplify. Now I have two versions of the fighter with subtle differences between them and powers with the same names that I have to distinguish between rather than new powers with different names and rules.
If they had created wholly new classes with unique names and powers, or wholly new builds, then I could incorporate them without confusion or difficulty. The way they've built them, however, is a hindrance, not a benefit.
I think the Essentials line may be great for a group starting out who've never played RPG's before, but if a newbie joins my group, which I've had plenty of experience dealing with in the past, I throw them in the deep end with a character and some dice and tell them, "Don't worry about the rules, you'll pick them up as we go along, just have fun playing your character," and that has worked every time so far so I don't see a need to change my formula.