I think I'm going to start a GS rotation next week or so. I have dabbled with them but never really given them a good go. Everyone seems to really love them so . . .
I do enjoy the two workouts on Terminator - I think I like the Viper one best. If you love the Intensity series then you'll love these - I think they are really great circuits.
I intensely love this series - the only ones I don't have are Harcore Extreme, StretchMax and HighStep - so I might as well have bought them all at once - all of the ones that I do have I love and use them a lot - I think they are pretty indispensable.