I just got Perfect Grand Prix a few days ago for GP2 and I think it's great.
The main reason I got it was the additional 11 tracks, including an updated
Silverstone, Nurburgring, Austria, Buenos Aires and Melbourne. It also has
Brands Hatch and Donington Park. The new tracks are nearly as good as the
originals. The readme file says certain detail was left out in order to
improve how smoothly the tracks run. I see little difference between these
tracks and the original track quality. The Austria track does contain a slight
blemish in that when you leave the pits it looks like the roadside cranes are
in the air. But this is the biggest problem I see with the tracks. The
program also includes many tweaks like paintkits, a way to change tire
compounds, and set-up utilities. It's easy and quick to install and you can
easily return to the original tracks, etc.