I have this car for about 4 years now. I am usually not an aggressive driver because I do not want to ruin the car (someone must think I am nuts to buy an M5 and drive like a grandma). I found it very powerful with the full power on. As I bought it in its first generation, I had many problems with oil leak, SMG failing, radio malfunctioning, and dead on the road (due to electronic problem in SMG). Well, after many trips to the dealership, it has been doing well recently. SMG is very sluggish between 1st and 2nd gear (it stinks especially when you are at a stop sign and want to speed up, but the car just gets "lazy"). Love the BMW full maintenance program. Love the iDrive too.
iDrive, 500 HP, comfortable seats
more responsive SMG in lower gears, able to remember driving setting instead of default driving setting, faster blue tooth connection, option for tint windows, traffic info in navigation system