Sorry if i came off as a fanboy, i´m not really. It´s just that i´ve tried all of them and played them extensively.
To me iRacing is way ahead in almost everything. The quality of the stuff is just mindblowing.
99% of what the driver can change on the FW31 you can change in game etc. (more things will arive later on but they are keeping it at this stage for now, don´t be fooled though you can set your car up just like the Williams team)
It´s just the tire model that is still very good but causes some unrealistic stuff like in all the other sims.
Kaemmer has been laying down 3 years on producing a mathematical tire model which probably hasn´t been done even in F1 and their simulators.
I suggest trying it, if you have no problems paying for quality then it´s a given for sure
Mclaren Electronic Systems has even started a partnership now providing the same telemetry as the F1 and NASCAR boys uses.
Promotions, (if i knew what i know now i would buy a year of subscription right away)
http://www.iracing.com/1-year/
http://www.iracing.com/buy-1-get-2/
If you have some time, then read this to get an understanding of what´s to come in August.
http://www.iracing.com/buy-1-get-2/
The truth will come out...