On the Community that you can have even serious disagreements over things going even so far as policy and still not tear each others throats out or name-calling.
Unlike a lot of other places.....
Sims
F1 2017: Career mode with R&D and the full rule set. (Also the improved handling over 2014.)
PCars 1 and 2: Dynamic Weather and easily set up MP sessions.
PCars 2: Day-Night Cycle+Lighting, the controllable slip, track and car variety. Also rating system.
AC: Mods and driving Physics, especially weight transfer.
R3E: Physics and the SOUNDS!!!! Also FRX-17, best F1 Car of 2017!
Also Licensed Series with their own rule-set, and even the fictional cars are great.
Track Atmosphere with the fans, they are a bit more alive than in the other sims.
Dirt Rally: Graphics, sounds, Differing Rallyes and CArs, and Group B!
Rfactor 1 (haven't driven 2 yet): Sheer ammount and variety of mod content for it.
Those that have it, dedicated servers.