I have several racing games, including the best of all racers, those on Dreamcast (F355, Test Drive: Le Mans, and Sega Rally 2).  I also have the "licenses-galore" Gran Turismo 2 on PSX and Sega GT.  Simply put, I have much more fun playing R4 than the "licenses-galore" simulation racers, and place R4 on the replayability level of Sega Rally 2 (my favorite of all).