Go test drive the Benz and I'm sure you'll end up keeping your X5. The Benz drove like a bus as others have mentioned. There's the slowest to no response from the gas pedal with an ON/OFF like operation from the brake pedal (pressing 1/2 way on the brake pedal does nothing, but then it grabs like hell after another mm of travel...almost as if I had made an emergency stop). Don't even get me started on the steering and suspensions. Very dangerous if you're not used to driving it that way. Almost got into a few accidents for the day that I had it! I will gladly pay the $5k-$7k premium for the X5 over the ML.