Can't speak for the Cadillac but had drives in the Audi and Lexus, and the BMW seemed like a much more involving and satisfying experience (this from someone who's not an out & out petrol-head, just a regular driver). Also not so keen on the somewhat 'frumpy' design of the Lexus, plus over here I've had nothing but bad experiences with Audi dealers.
All very subjective of course!