If you think Grid is difficult, wait till you play NFS:Shift
Grid is quite arcadish and very playable with a controller (I used the Xbox360 controller for the PC) unlike Shift which definitely needs a wheel. It took me a while to tweak the sensitivity settings until I was perfectly comfortable with the handling. Grid's cars have hair-trigger responses so adjust accordingly. Also, brake early into the corners.
The AI can be a bit nasty, but is still far better than the psychotic rubberband AI in Shift. The key is to get far ahead of them so that they can't bother you, otherwise just nudge them off the track
Seriously though, Grid is an excellent and fun racing game.