Some of the reasons why I prefer the S4 over the WRX:
Despite what some of the magazines say, the S4 at least matches if not outperforms the WRX in acceleration at lower speeds and definitely exceeds it at higher speeds. Also, it has a higher top end and is designed to stay there all day if need be. Nice on long jaunts across the desert.
In day to day driving, the torque obviates the need for the downshifting (which the WRX requires) and makes for a more powerful feeling and smoother car. Great for climbing the mountains.
It has less turbo lag and better throttle response, especially noticeable in passing maneuvers where real world performance comes to light
The S4 looks better than the WRX. Females, in particular, repeatedly express their disdain for the appearance of the WRX (i.e. the scared catfish look). Not meaning to be disrespectful here but, sorry, that's what they say.
It is built stronger and better able to protect the occupant in crashes, roll-overs, etc. Also, it has better airbag protection (side curtains as well as front). The car is eminently survivable as evidenced by crashes at well over 100 mph where the occupants walked away vs. fatalities which have already been documented in WRXs at lower speeds. To me, the car isn't important ... my life is. One's replaceable, one's not.
Galvanized metal construction with higher quality German steel and a superior corrosion warranty means better rust protection.
The interior is sumptious, the best in the business. If you want to impress a new girlfriend, do you take her to McDonald's or the best French restaurant in town? 'Nuff said.
The car is smoother and quieter. They don't call it "The Silken Rocket" for nothing. Much more enjoyable to take on a long, cross-country trip.
The ultimate tuning potential of the S4 is greater with a stronger block and transmission. 400+ HP kits are now hitting the market with 450 *reliable* HP very obtainable.
The 6 speed means quieter, more economical high speed cruising.
The quattro AWD system is slightly superior to the fluid coupled system of the WRX. With the slightly better AWD system and the heavier weight, the S4 has been shown to be a superior handler in the snow and ice.
The S4 is a better winter car in other ways. It has heated seats, heated mirrors, heated doorlocks, and heated windshield washer nozzles as well as a superior climate control/heating system. Extremely comfortable with completely clear windows in the nastiest weather. In addition, the ski sack means I can fit my skiis *inside* the car.
I like the look and visibility conferred by the Xenon headlights with nighttime high speed driving. I also like the rear fog lights (an excellent deterrent to tailgaters).
I like the smell and feel of a leather interior and the easy adjustability of the power seats.
Although it's a hot running engine, the dual fans ensure that this engine never, ever overheats in summertime stop-and-go traffic.
The car has a prestige aspect. Business clients are more impressed and valets treat the car with more respect than cheaper Japanese cars.
No insults meant for the WRX which is an excellent car for the money but I think you folks overlook *all* the reasons why S4 owners buy their cars. It isn't just 0-60 and 1/4 times and price.
To each their own.