Middle children, according to popular myth, are often the most unhappy of a family's siblings. They struggle for recognition, overshadowed by the eldest child's maturity and experience, while competing for attention from parents forced to concentrate on the youngest child's often more pressing needs.
Not so for BMW's middle child sedan, however. While the BMW 5 series is bigger than the popular 3 (the company's bread and butter sedan, and a blast to drive, too), and smaller than the luxurious 7 (deservedly one of the darlings of the luxury sedan set), it has its own personality and its own reputation. It's really the 5 -- especially in its highest performance livery, the M5 -- that's most often equated with being "the ultimate driving machine".
Full review here