 Great quality control, good front seat comfort, marginal rear seat comfort, but unreliable acceleration when you really need it Sometimes the acceleration when needed in traffic is good, other times the car places you in harm's way by not accelerating for a few seconds. Completely unacceptable in my opinion.   We had a Mercedes C300, traded it for the Audi A4.  We will go back to Mercedes with the next purchase.  Audi has attempted unsuccessfully to find the non-acceleration problem.