I cross-shopped the Lexus IS/GS, BMW 5 series and the Acura RL. Stayed away from Mercedes due to past experience. RL provided the most rewarding driving experience combined with the most features for the money. It is also very reasonable to insure. Fuel mileage has been in the 17-20 mpg commuting in traffic.
Quiet ride, navigation and handsfree bluetooth system. Subtle exterior that does not draw attention.
No premium fuel requirement. Combine the buttons for handsfree and voice activated-nav. Move door handles towards the back of the door to get better leverage when closing. Door handles feel flimsy.