I gave the rFactor 2 demo a chance and I have to say, that wasn't bad! So I caved in and bought the game for 15 Euro (Steam sales yay!).
I love the AI and the game play feels really good, I love how clean the game looks, the sense of speed vs AC and how it performs on my outdated hardware (GTX 970 on a 144Hz 1440p screen is not always pretty).
However I'm kinda disappointed in the stock content compared to Assetto Corsa. No GT3 cars, no LMP cars or big brands (Audi, BMW etc), no circuit de la Sarte, no SPA etc. Guess I should have done some more homework, oops!. To alleviate this, are here any must have expansion packs (GT3 pack?) and mods that I definitely should grab?
On a side note, I also tried out Raceroom since it was free but oh boy, I did not like that so much content is walled off, I understand the game is free but I have no idea how much money i'd end up spending. the game played very smooth though!