Chatty DM has posted a fairly in depth review of Keep on the Shadowfell, the first official 4th Edition D&D product (excepting minis and preview products). 

Of particular note, the adventure comes with 4 battle maps of key locations, although they are reprints.  Nonetheless, the inclusion of battle-sized maps is a welcome change and should make it easier for DMs to prepare adventures and increase the fun for players.  (update: there are also 2 new battle maps for a total of 6 - thanks to Chatty for the correction)

The adventure includes a 16 page rules primer and an 80 page booklet containing rules for the Dungeon Master and the adventure itself.  Overall, he appears to like the product and is mostly favorable on the rules and the adventure itself.

This is a well made adventure that showcases what low-level heroic-tiered characters and foes can do. It’s a simple, straightforward story that puts into play some of the core 4e fluff (The Shadowfell, Orcus, points of lights and so on).

Not everything was rosey though as he noted what I consider to be a major flaw in the product:

One word of warning, and my main beef with the product, the booklets are very fragile (paper is easily damaged) and the ink smudges very very easily. I’ve been handling this one for a few hours and pages are already covered with enough fingerprints to incriminate me without actually having to call the local CSI.

Thanks to Talae for the scoop.  You can discuss this article in this thread on our forums.