Picked up the M6 today and I couldn't be happier with it. After many years with sedans I'm happy to be in something that is completely different. I can't really comment on how it compares with an M5, but it's a night and day difference between this car and the 550i.
I was a bit dismayed to find that the car had a warranty claim before I picked it up. It appears that as they were prepping the car the salesman noticed that the floor mats were defective since they were missing the M6 logo (standard 6 series issue) They actually warrantied the factory mats to replace them with M6 mats
First impressions:
Break-in will be really difficult. 1090 miles to go...
In P400 mode the car doesn't have noticeably different performance from the 550i. I'm sure that impression will change once I can spin it up over 5500. In P500 mode the car is simply amazing.
This is a July build and it appears to have the new iDrive hardware minus the preset buttons. There is no more haptic feedback on the controller knob and the speed is vastly improved over the 550i (MY 2006).
The back seat is truly useless. I usually put a paper shopping bag on the floor behind my seat to collect empty water bottles. There isn't enough room for it in this car!!
I also laughed when I discovered that the leather binder for the owner's manuals doesn't fit in the glove compartment.
I was able to snap off a couple of photos during the delivery: