What you like most in car racing game, choose only one of the options and the game that matches your choice in question:
1) Graphics
2) Sounds
3) Physics
4) FFB
5) Immersion
6) Driving
I would say a balance between everything, but if I have to choose one, it would be "Immersion" because I think it is something that cumulates everything (and so, a balance). And so would put it as number 6, not 5.
About what game does better each thing, I might say:
1. Graphics: pCARS as it is both "light" and awesome for what I could see on videos (not owned);
2. Sounds: Automobilista & RaceRoom Experience, each in their ways (both not owned), but sincerely surprised that Gran Turismo is getting somehow closer to reality (I think M6 GT3 is pretty close), though PD keep trashing a bit the final result. Assetto Corsa really good, pCARS sounds partially fake and rFactor 2 simply can't stand a chance apart for few mods;
3. Physics: rFactor 2, and no one can discuss about this. The weight and importance of the maths this simulator computes are not closely compared to any of the other games. The only 2 that gets "not-that-close" are Automobilista and Assetto Corsa. But pure physic not necessarely means realism, and I'm one of those that thinks rF2 is not that "best" in terms of reality as the cars feel too slippery, even professional mods;
4. FFB: I would say Assetto Corsa, but not tested interesting games like Automobilista. So I might be wrong;
5. Driving: Assetto Corsa. As I said above, rFactor 2 having best physic doesn't mean the best "driving" experience, and as I said there the cars feels too slippery. Like driving with Bias-ply tires even in modern cars, with lot of information but low grip. But it is said about Automobilista, although being based on a updated version of ISImotor 2.0, Reiza changed it to "fix" this problem first and then step to a real physic engine update to try catch ISI (now Studio 397);
6. Immersion: So, the balance out of overall Graphic + Sound + Physic + FFB + Driving... I might have to say still Assetto Corsa. But have to say, Assetto Corsa is missing the day-night cycle along with the rain. And these are things that Automobilista got, so at the end this latter one might give the Kunos title a real challenge depending on the kind of immersion a driver wants. Personally, being an endurance simdriver, I would select for this final one Automobilista as winner, but not actually owning it not gives me the chance to evaluate correctly, so atm I keep my Assetto Corsa pick.
P.S.: I'm probably gonna purchase Automobilista with the next Steam sale, so that I can "close the gap". Also gonna get Gran Turismo Sport when it will come out.
if someone is interested to watch)
).
GT6 sounds bad compared to Wipeout HD/Fury music playback even on same DTS 5.1 format, less clarity on high frequency range, harsher mid range and lack of low frequency smoothness, simply no contest. Like having different music player. In Wipeout HD/Fury, the more you crank the volume, the better it gets, the music player alone worth the price of the game 
