Zacuto's Great Camera Shootout '08 from Steve Weiss, Zacuto USA on Vimeo.
Zacuto have brought together four film makers and asked them to choose between a range of cameras starting at the top end with film, the Red One, all the way to the Nikon D90. In the mix was also the Canon 5D MkII.
At the end out the "shoot out", two of the four film makers picked the Canon 5D MkII as their camera of choice for documentary work.
You can watch a bigger version here. There is also a 720p HD version to download from the site. You need to first register for free and then download the M4V version which is to the right of the Vimeo page.