What multiplayer PC racing sims are you playing?

[Aashenfox]

As title really. I used to play Race07 a bit, was thinking about picking up a serious Fanatec wheel and building a little cockpit thing. Was wondering what people are playing competitively these days? I hear Asetto Corsa has great physics, important, but iRacing has a huge playerbase. Any thoughts?

[TT350]

Asetto Corsa looks spiffing. A friend gave me a demonstration on his setup. Unfortunately I don't have a decent PC these days but if I did I'd be on that.