In-Camera HDR vs Photomatix

[hulk]

So,
I've just learned that quite a few cameras can combine pictures in-camera to achieve better DR. From what I understand, Nikon just calls it "Multiple Exposure".

Does anyone know how this compares to doing the combining with Ps or Photomatix? I imagine for a surreal look, Photomatix can't be beat (don't like those too much though). But what about realistic shots? Is it worth the risk to do it in-camera as opposed to in post?

Edit: Holy crap! It embedded the Youtube video. Cool!

 

[KmH]

But they can't do the image merging processing Photomatix does before tone mapping is done by the user.

I didn't see much detail in the dark portions of his final images.

I gotta get me a D3. Nice looking screens.