Amazing.
I launched the game directly after installing and did a 'test day' with the C7 on Spielberg GP. I did about 12 laps and a blast. I was surprised to see that there weren't any realfeel settings included. After that, I tried the Viper and the Ferrari. Both of them felt great and actually not like a mod. So I moved on to the prototypes and they all reminded me of the rF1 Enduracers mod and in a good way, they feel even better.
There wasn't as much grip in the GT cars as I expected there to be, which doesn't have to be a bad thing and the tires heat up quite quickly when you slide around a bit. Although the loss of grip isn't as bad as in the Blancpain mod we currently use.
Another downside is some graphical issues. For example, the Ferrari's textures (and rearview lcd) sometimes disappear and are placed somewhere in the map. I had that same problem with the rF1 mod, but in that version it actually hinders your view. Now it's just a bit annoying. There are also some minor flaws, like the shiftlights in the viper not working and the car status on the C7's lcd also not in use. Luckily we have the hud for those things, so it isn't game breaking.