All hear say. I heard said that Spa is the best, Never been there so I can't confirm.
I'm still slightly aroused thinking of Mugello though.
In any event, all I care about is room to line up a pass, and the room and opportunity to make a pass IN THIS GAME. I still think Brno is the best for that. It's wide with long straight into tight corners, yet you can carry different lines through those corners. The elevation changes also make thing interesting.
But then there's a whole bunch of old tracks that I would love to see brought back. The old Hockenhiem for instance. The old Mexico City.
The updated Kyalami looks like it would be good too.