A sort of GT-/Forza-like experience, but with much more realistic handling physics than GT-/Forza-style physics (if it is like PCARS2, it is not a close comparison) and PCARS content and features. Dynamic+seasonal weather on every one of an exceptional spread of tracks, for one example.
Part of the "fun" here is that its handling model should be far superior to GT/Forza. Handling is the whole reason I play sims; the main reason I even bought a Playstation. Pitstops are just a gameplay mechanic and classes are just arrangements of cars. I don't prefer what SMS has done with those things, but being able to buy, paint, customize, and upgrade cars in a sim with Project-CARS-caliber physics is paramount.
Handling is the backbone of the whole gameplay experience from "Start Race" to "Return to Menu".