Huh? Assetto Corsa is probably the most true-to-life driving sim out there right now. While Project CARS may be a better "general" racing game by sheer variety of vehicles, tracks, and other features, AC wins out on pure realism in regards to vehicle handling and physics. And for many people, the $50 price of admission is worth it just for that.
I enjoy Project CARS. But I don't really consider it to be a racing sim. Some people do, but these are the same people who consider games like Gran Turismo or Forza to be racing sims; games that certainly lean on the side of realism, but don't reach true simulator status like Assetto Corsa, rFactor, iRacing, etc, etc.
Nurburgring Nordschleife is available for both games (you must buy it in an expansion pack for AC). The difference, however, is that the AC version of the track is a
laser-scanned model of the real thing down to a 2cm resolution/accuracy. The pCARS version, as far as I know, is not.
On the surface - without spending much time in either game - Assetto Corsa
looks like the more disappointing title. But where it lacks in content, it overshadows pCARS in authenticity.