It depends on which G-forces you are talking about. Right now there are the g-Force Sport and the g-Force T/A KDW 2. You can do much better than the Sport version since in stock size they run $105 a piece and you can get Azenis RT615 for $1 more a tire.
The KDWs look very cool, but they cost $30 more per tire than the Azenis and $37 more than the Hankook Ventus Rs2 Z212. The only thing I can see the KDW being better in is treadwear. They are rated at 300 while the other two I mentioned are 200.
I've never owned them, so I can't really comment on how good they are. I'm just saying I would never buy a comparable tire that cost more than the Azenis RT615, because to me I think those tires are the cream of the crop for summer tires. When they wear out I might give the Hankooks a try just because they are a little cheaper.