Picked up a low mileage 07 M5 after reading some tough reviews on fuel economy and terrible SMG transmission. Don't beleive them! This car is a drivers fantasy car...the motor and transmission are incredible and smooth, you just need to invest some time and figure it out. I am getting 19mpg sriving 80mph with "power on"...it'll go from 50 to 100 fater than I can write it, the paddles/F1 shifiting is perfect. I have a 911 and a CayenneTurbo...love them both - this is better. If you love to drive, find one of these M5's and own it. Also helps if your brother is a state trooper, you will get in trouble, promise.
too many to list - the motor / SMG combination is off the hook. I lucked out and got a sport pacakge model - full leather makes a huge difference in the comfort
several imnprovments on the iDrive display but not the mechinism itself...people complain about iDrive, liek the car just need to figure it out and it becomes very intuitive.