Happy to say I received mine from B&H on Friday, and I love the lens. Did some informal tests first thing (one shot attached), and then took it to an event Saturday morning.
The attached shot was taken with the front-element about 16" away from the peppers, which is close to the MFD, at f/2.8, on a tripod. Not cropped, and the sharpening is the LR5 default.
I've looked at about 400 images taken with it, of details, of models, group shots, flowers...Any focal length and distance from subject, this is such a huge improvement over my 24-105mm and my 9 year old version 1 of the 24-70mm, that I know I made the right decision and will commit to it by cutting the UPC out of the box for the rebate later today.
As for the MFD, maybe Canon was slightly optimistic saying it could be 1.27 feet, but when I shoot events, I don't get that close. I'm happy with 20-24" working distance for detail shots, which so far is working great with this lens. If I did try to shoot closer, I know that any lens-shake is going to be magnified.
Ok, I guess if somebody wants to use this on a tripod at the absolute MFD, they might wish they had a true macro lens, but that is not why I bought my 24-70.
To my eyes, it provides very good sharpness starting at f/2.8, and I am super happy with the silky transition to the OOF areas and the bokeh itself.
I'm thinking that somehow the way this resolves onto newer sensors somehow matches the sensor array far better than the older 24-70 or even the very popular 24-105mm. Sure don't know the science, but it just plain works!
In the past, I bought lenses or other gear and then kept second guessing myself. I know about agonizing over a choice, and then agonizing again over the decision. With experience, and beginning to understand real-world vs theoretical/charts/neuroses, I'm slightly more easy going. This new 24-70, despite the cursedly high price, fits my style. Good tool, I'm sure.