When I bought my '06 QP at the tail end of 2012, I had a straight choice between that or an M5. The sensible choice for what I wanted to use the car for - long journeys with the family, dog and luggage - was the BMW. It would do everything I wanted it to do with ease.
It's just that after my two years with a 4200CC, I had to have the Maserati. They have a special cache that can't possibly be matched by the M5. Nor most other saloons for that matter. To be honest, as things currently stand, I cannot ever see myself without a Masser somewhere in my life.