Took the 'new' camera out last night to one of my favorite locations to 'test' it out. For an entry level camera it handles very nicely - especially at night - since the large lcd screen on the back does double duty as the information screen as well. There are also a few nice little touches, such as a count-down for the self-timer and the cut-out sensors when you bring your eye up to the viewfinder. Overall I was very impressed.
The vertical grip creaks and groans a bit, especially given my usual 5D experience, but the battery power seems consistent and I don't think it's likely to break anytime soon. The fit with the camera seems ok, and it certainly handles better with it attached.
The lenses autofocus quickly and reasonably quietly, although I didn't really get a chance to push them to the limits given I was shooting landscapes. Sharpness appears to be acceptable from the results so far, but I will do more tests against my 17-40 f4L soon. That will be a real test.
So far so good. I enjoyed using the camera very much, and it has an excellent user interface. Kinda wish some of the features were on the 5D as well. I can tell I'm going to enjoy using it, and will hopefully use it a lot more soon. More thoughts and pictures when I do.