Started off in 2003 with the 740 since I wanted a nice traveling car, the 335 was to replace my daily driver which died and the X5d was just for giggles.
I still have them all per my sig.
Bought BMW since MB supposedly has no soul, Lexus drives like a Toyota although a really nice one and could never find the right Audi when I was looking.
The Audi drives really nicely but is definitely softer feeling than the BMW's
I think the X4 drives like crap, didn't feel like a BMW at all. It felt like it was going all over the place and it was a brand new loaner.