I've had my 2014 3.7 for about three months now, and have several loves and hates - love the keyless entry, remote start (Chicago weather), steering wheel paddles for downshifting to pass, etc., driving comfort, fairly quick, looks great clean (Black car).
Hates - proximity sensors occasionally go off seemingly at random, right side mirror has a mind of it's own, turn signal way too loud, 14 mpg in town, can't keep heated steering wheel / seats "always on", I kind of miss the shifter.
But after 3 months I do not miss my old A6 at all. The MKZ is a nice car but black on black - have to wash/clean it almost every day! (Delta Sonic car wash is around the corner)