I currently have a E46 M3 ZCP and wifey traded in her 2011 X5M about a month ago for a S6 and it really made me start looking a lot harder at Audi.
I was kinda in the market for a new car, preferably a 4 door and went to the Audi dealer to test drive an S4 but they had a BEAUTIFUL RS5 sitting there, so, I just had to drive it. Needless to say, the car is flat out phenomenal! Now, I'm a huge BMW M fan but I can't deny that after driving that RS5...I am seriously considering it.
The car is gorgeous inside and out and it just looks and feels more expensive than an E92 M3. Steering is so much better than most on this forum realize. Its heavy, tight, and very precise. Not as perfect as my M3 but damn good! Nothing like the other Audi cars. Engine and exhaust note sound amazing....especially the throttle blips. It handles superbly...really holds the road, doesn't understeer, and feels very planted. The car inspires a lot of confidence in you while behind the wheel. Audi's MMI system is top notch and I definitely prefer it over iDrive. The navigation with Google Earth is awesome! And, of course....I just love its a NA V8!
All in all, I'd love to own this car and never thought I'd see the day where we'd have two Audi's in the garage but I can't deny how great the S6 and especially the RS5 really is.
I'm still thinking about it because I didn't really want to add another 2 door sports car/coupe but the RS5 was just that good.