I just wanted to chime in here as someone new to D&D as well (the intended target of the new Red Box!) who has picked up the starter set (my store also offered it early! hooray!).
While I've been a gamer for years (MMOs, video game RPGs, CCGs, minis games, etc.), I've never tackled D&D. A buddy of mine decided we should start playing with a few other friends, and his wife, and it looked like the Red Box would be the best way to start. Nice timing on that.
I've been able to peruse the 4e books, and have listened to many of the pod casts (mostly the Penny Arcade stuff, being fans of theirs), so I got a grasp on those rules before diving into the Red Box content.
The solo adventure to start off character creation was quite enjoyable. It led to a lot of questions given my 4e knowledge. I wanted to know why I was being given this or that stat, etc., but overall, it seemed a nice way to get people going.
It would have been nice to get a little more movement and combat rules in the player book, though (instead of being hidden away in the DM's book). 4e seems to go smoothly enough if you have a DM that knows all the rules, but if you're both as clueless about it, that doesn't make things easy.
There also appear to be a number of errors in this first print [I've noticed the 'Errata' thread you've got going here]. Some of that was certainly confusing (powers being referenced when they weren't actually included being the worst of it). And it's odd that something like Magic Missile is actually different (and way too easy, I think) from the main books.
For all that, the Red Box has gotten us on our way. Those we've encouraged to play that were maybe a bit wary about RPGing are having fun. We've not finished the group adventure, but plan to do so this Saturday. Then, we're liking moving straight on to normal 4e. We don't really want to wait so long for the other Essentials products, and feel like we're not playing the 'real' version of the game - at least the couple of us that are 'gamers'. So for that, mission accomplished Red Box. Mission accomplished.