 I cross-shopped the 328i (xDrive), TL-SHAWD, A4 2.0, and IS-250AWD.  None of them came close to offering the same blend of performance, handling, features, technology, and usability as the G37xS.  The engine is extremely powerful (pulling away with four passengers up a hill is still easy to elicit a "Whoa" from everyone on board), the chassis handling BMW-like (read: near-perfect), the technologies (voice control, music box, swiveling headlights, laser cruise, traffic gps, etc. etc.) both cool and easy-to-use, the seats bolster you in like some high-luxe sport cars, and the overall experience is extremely satisfying and fun.