rFactor, Racer and Assetto Corsa comparison

in a comparison between rFactor, Racer and Assetto Corsa, to play with tracks and rally cars, what would be the best of them? and in asphalt tracks, which one would have the most realistic physics?

i think that is racer the best,,,but if there would be traffic for the roads like city car driving or anything else,,it will be the best game ever seen,,,more realistic