Just checked DP Review and verified on Canon's own site. The 6D's max shutter speed is 1/4000, not 1/8000 as stated on this site.
Another point: I originally got excite and thought this would make a fine backup to my Mark III. Now I realized this is not for pros, but for prosumers. However $1300 or so more than the 60D and even more for T4i is somewhat out of "upgrade" price range for non pros.
What Canon should have done is releasing this camera without GPS and Wireless. Hell, they could even release the whole thing in plastic (it's currently alloy body and top plate plastic) in order to get the price down to $1500 or so, then they really have a winner on their hands. Most crop factor Canon users will want to upgrade.