Was there this weekend for the BTCC. I have to say that the spectator area in the middle is great and you can see most of the track, although they did not have speakers wired up there so we heard no commentary. If you want the commentary then probably somewhere in between Sunny out and the complex just up on the hill next to it is a good vantage point. The grandstand wasnt as good really as most of the action happens at the complex and the hairpin.
So in short, if you want to hear commentary, then on the grass bank after sunny out, if not then the middle.