The official cars and well made mods for Rfactor are closer to reality than most of the cars in GT5. People who have only experienced the console can't understand the quality of the sims available on the PC, i love GT5 but some of the vehicles available through mods in Rfactor are amazing. You can go around saying that they aren't close to real life because they are not official, then the same can be said for all of the cars in GT5.
GT5 is a great racer, best physics on any console game and in some ways it works closer to real life than the best PC sims, but as an overall view GT5 is still a fair bit behind the PC sims in terms of quality, the biggest area for me is braking and the way the cars react under braking. I'ts not about the game being easier to drive, because even iRacing in some cars can be easier than GT5, its just getting everything feeling right, mostly with the tyre model.
Lastly GT5 isnt a racing sim, the events and racing in the game are nothing like real world racing, it is simply the driving that is simulated. The PC sims have more in depth detail and accuracy in the physics and in the general feel of simulating real life race events, and i would recommend any GT5 player who has not tried them to give them a chance.