Own a 2012 S5 after testing the 2.0 A5 in pretty much every configuration available at the dealership.
I'm not sure why Edmunds thinks the steering is "contrived" or "artficial" because my experience is of an extremely tactile and responsive control system. My own gas mileage IS actually improving as I learn how to properly drive the car.
Now at 1000 miles I am getting closer to 26 to 28 hwy and 15 to 19 city mpg now thanks to my judicious use of the responsive cruise control, and active mileage monitoring system, and I can adjust my driving style to suit.
Well-mannered in traffic when it needs to be, and becomes an elegant beast when pushed with very little effort.
Audi has improved on the older S5 model by adding the Rear Sports Differential where you can make the engine more aggressive, the steering tighter, and the rear wheels shift torque sidesways when cornering. Because of the dynamic mode, this S5 feels much faster, tighter, and much more fun to drive as it incorporates the technology of the new S4.
It feels as fast and fun as the new S4 compared to the 2009 S5 I tested.
In terms of gas mileage, I achieved 22 MPG on my initial break-in out-of-town trip (mostly highway), and 19 MPG in city driving. I feel that highway driving could easily get to 25-26MPG after break-in.
Beauty, performance, & the V8 sound makes the s5 as class of its own.