It all depends on the car. Some people appreciate the look of a stock fox but want the added performance of 17 inch tires (not to mention a much wider selection of tires). I know if i had a super clean unmolested aero car, i'd probably want the Pony R's. Plus if you're trying for a sleeper look, it does take a bit of a double take to realize they're 17s.
Just got the SC's with 315/35 mickey thompson drag radials on last week. Kinda bummed about the backspacing on the 10" SC's...would look better with the 315's if they had about a 1/4" more bs to tuck under the lip a little bit. As it sits, it is flush and have about an inch between the wheel well.