Definitely not a sim,all you have to do to find out is to get the c9 mercedes out for a spin at Nurburgring with both games assetto and project cars ,you will soon find out the huge difference between the arcade and the sim.
I think we all understand the words arcade and simulation ,that's why i think that project cars is a bad simulation ,it is impossible to hit full throttle in a 900 hp beast out of a corner and nothing to happen not even a decent spin .If you do it in assetto you'll find yourself spinning out of track. I don't say that in the assetto the representation is super exact as it is in real life but i can say for sure that is far more near to it.