I’ve been on iRacing for 1-1/2 years now. An instructor at a track day told me about it. I wasn't a gamer, but it’s my favorite hobby now and I’m usually on there a good amount, especially in the winter. I’ve been running the 1989 Nissan ZX-T IMSA GTP car in the Kamel GT series most of the time I've been a member and do very well in that series. I also do most of the endurance events with a team.
My rig is an Obutto running a OSW direct drive with custom Sam Maxwell wheel, HE Ultimate pedals, Oculus Rift, and Fanatec shifter. There is too much flex in the Obutto. I haven't upgraded it yet because I'm debating on weather to go to a motion platform. If not, I'm going to just buy a Sim-Lab or build an 8020 rig.
I mostly use iRacing because the competition and community with real people is by far the best available, physics are the best, and racing feels the most realistic. I'll occasionally play Project Cars 2, Assetto Corsa, Raceroom and RFactor 2 just to play around in other cars I like. All in VR though, it's just so much better. Flight sims like X Plane 11 and DCS are pretty awesome in VR as well.