Pre-ordered on March 18th, arrived in Cameraworld on the 19th so I have had some time to check out the handling & features.
Reassuring build and a joy to use, a step up from the 5D2, and learnt from the 7D (both now sold to pay for the 5D3).
AF is great, you need to spend some time with the book and practice to get the best from it, at least I did.
I have no interest in video so there was considerable soul searching to upgrade the 5D2 for which I found the IQ perfect for my needs. The 5D3 moved this on some more, side by side it is possible to see the difference on a big screen.
My preferred photography is macro with insects, and being quiet certainly helps, as does the speed of focus especially at the centre points.
It's a lot of money for lots of little steps forward - but I have no regrets parting with two bodies and settling for this one.
Just wish Adobe would hurry up with RAW support for Lightroom...