I have driven every car under the sun except for maybe the Bugatti's and McLaren Merc. This is a total favorite. I owned a 1995 version which had some electrical and suspension problems. This 1999 version is a beast with refinement and awesome handling. I grew up with a test engineer father and we absolutely thrash our cars. This 540i holds up better than any vehicle I have tried to thrash. I have owned Australian racing Toranas, several Subarus, a few BMW (540i, 3 series) and a Lotus Espirit (twin turbo). Overall this is the best machine I have had the pleasure to own or drive and it's handling is 2nd to none in the luxury car stakes.
Power, drivetrain, handling (cornering) and internal comforts.