My take on PCARS 2 vs. GT:Sport from playing on a PS4 Pro on 4K HDR TV with the DS4 controller:
(note that I absolutely enjoy both games and wouldn’t want to get rid of either one of them)
* PCARS 2 is hands down the most realistic game, sim if you want. The car classes and their handling, the real life tracks, the dynamic weather, the time of day, the seasons, the driver career, livetrack 3.0 etc all contribute to that.
* PCARS 2 also gives the most diversified racing experience with so many tracks and weather conditions plus rallycross and ice/snow surfaces.
* GT:Sport however feels more polished, it has that GT feeling of old with the driving school missions, has a familiar GUI and some of the best menu music I ever heard in a game.
* Part of that polished GT feeling also comes from how the cars handle, GT:Sport has a more simplistic handling/tyre/physics model than PCARS 2, but that also means each car is easily to step into and drive, you won’t run into those situations like in PCARS 2 where you would think the game handles bad because maybe you didn’t understand you were using the wrong tires under the wrong circumstances.
* What I also absolutely like in GT:Sport is the mature feeling (compared to Forza then) from the museum info, the scapes, the intro video etc.
I have not tried multiplayer in either one game but I did watch a significant amount of videos of both in multiplayer. I’d say GT:Sport is your easy to step into multiplayer and looks incredibly fun to me. PCARS 2 has that more realistic sim-feeling where you just don’t want to jump in unprepared.
If you can get both games I can only recommend doing so. They complement each other really well IMO and can coexist perfectly next to each other.