I drove an E60 M5 just before I turned it in for an X5M. I needed the space for my kids. This car is almost as fast and grippy as the M5, yet manages to be more comfortable and usable. I took it on a ski trip where snow was everywhere. My dealer warned me not to go on snowy hill like other SUVs but, it managed to pull it off well. It had not ample but enough space for two babyseats and all the luggage and equipment for family of four weekend ski trip. The gas mileage is terrible, but if you have to worry, try HONDA. THis is not for you.
As long as you don't mind the terrible mileage, it's an amazing car to drive. Wolf in sheep's clothing. To the casual observer, a soccer mom SUV, but it's as close to the acceleration of a roller coaster that you can get to.