Ok, I've just spent the past 10-15min looking through the Dungeon Masters book...They really went all out for this. In fact I would say that if this had been out when the PHB was released you could have run a rudimentary game with just the boxed set and the PHB (It even has a nice mini-monster manual in the back). In fact it's so close to the red box (on the DM's side of things) that I almost feel more disappointed they didn't just go the extra mile and flesh out the PC side of things. I would have paid another five dollars to have some basic character creation and advancement rules.
Included are...
1. Dungeon Master's Quick Start Rules: Same as KotS, but more fleshed out with a listing of conditions, and a step by step guide to Using Monster Stats.
2. Adventure: 3 encounters, a little dialogue to start it, a small area map and home base (Harken village) for the pc's as well as advice on integrating PC's into the setting with backstories, etc.
3. Creating Adventures: A section that discusses the different monster roles, Encounter Components, Encounter Settings, Skill Challenges, Traps and Hazards, Creating Dungeons (utilizing tiles as well as the "parts" of a dungeon like corridors and random encounters)
4. Monsters: 25 pages of monsters (Nothing new, though I wish they had threw in a couple that weren't in the MM).
I definitely think this boxed set will be very good for teaching someone to DM 4e, and in that aspect I give it 4 stars. As far as the PC side I gotta give it 2 stars(it's just KotS revised without the adventure). The Tokens are cool and sturdy though I kinda wish it did have minis of the PC's (just so I can get my hands on a non-rare Dragonborn...lol). The dungeon tiles are a wash, but only because I have DU1 already...hey would be cool (though I wish it were more) for a new player.
One other note though, I'm not sure...but I don't think the errata on skill challenges has been incorporated into the starter set, so this might be an issue to some.