This is interesting for me as I have done a bit of video using iPhone.
Generally I will import iPhone video into Final Cut X and edit it there.
Sure, iMovie on iOS is cool and all but I am used to FCPX and I prefer to work this way.
Obviously with FCPX you can do colour correction and grading etc so who knows what kind of post they have done here.
That said the video looks pretty decent.
The stabilising equipment is a big help of course and with small hand held devices like iPhone you need tripods and so forth to get the best results and with better software enhancements for motion capture that keep coming it'll only get better.
There isn't much point comparing the iPhone (or any phone) to a dedicated Canon or Nikon camera for obvious reasons - what this proves (aside from using several phones additional hardware) is that phones can be used very effectively as video capturing devices to create some excellent content.
As always the user plays a big part in the end result - shaky, badly shot video can be had from even the most expensive RED camera if you have a bad operator.