Been running a 4E game since it debuted. In fact, I posted my maps (crappy though they were) for that campaign when I introduced myself here. I like 4E, but it's not D&D. It's an entirely different animal. We (my group of 10 players and I) play 4E in an ongoing campaign, with occasional breaks for other game systems. Right now, we're alternating between a GURPS game being run by a friend, a Savage Worlds campaign (with a pulp/fantasy feel), and my 4E game.