I found that that works okay for something like a car interior scene, but I use a boom stand and shotgun mic for filmmaking. I make it a point to get closeups and get the shotgun mic up close. When possible, I get someone else to hold a pistol grip or a boom pole, which sounds 20X better than the camera mic.
A few weeks ago, I shot an event, where the main speaker was supposed to stand at the podium, so I set up my DVX100 and a Sennheiser mic by the podium (on the tripod and boomstand). This job didn't afford for another camera man, so I used the HVX200 to get handheld cutaways from the audience. Well, the speaker wandered away from the podium, almost the whole time!
The audio that I got on camera sucked, especially interviewing people in a room full of talking. Fortunately, the boom mic still picked up sound, from the guy speaking, that I could tweak, even though it wasn't close to what was going on.
I'm not really set up for event videography, but in light of the economy, I have taken a few side jobs. I was surprised though, in this situation, how much the on camera mic was not up to par. The shotgun mic saved my butt.