Keep on the Shadowfell was the first adventure I played for 4th edition. It was pretty fun while it lasted, the beginning went strong and from what I heard from the DM the adventure gives tips on running the game and some rules to remember which can be useful for starting DMs. However, the adventure eventually became a dungeon crawl once we got inside the actual Keep, and it was one combat encounter after another. We'd finish one combat, we would move to the next room and there would be more combat. We eventually just got bored of the adventure, the DM waved his hand and we were fighting the BBEG. Still, the combat got too tedious. If you're running the game, I'd suggest cutting down on the combat and adding more roleplaying to it, or simply make the dungeon smaller.
The other published adventures I've played were Scales of War, which comes with WotC's Dungeon magazines starting in issue 156. I liked the simple introduction (You're in a tavern. Hobgoblins break down the door. Roll for initiative.) and how it all snowballs into a larger adventure. The DM (The same one that had run the KotS game.) later told us he had made the dungeon smaller and used only the things that he liked the most from the adventure, and there was less combat in every room and more exploration and roleplaying. I did enjoy it, and I'd recommend it simply because it was loads of fun.
tl;dr: WotC adventures have a lot of dungeon crawling and combat, so use only the ones that you think are cool and don't add combat for the sake of making adventures last longer. (Unless your players love combat.)
