I did a rotation of "Get Ripped to the Core" and "Ripped: Slim and Lean" for two and a half weeks (does that count as a rotation? LOL!) and I plan to do a longer one soon.
I really like GRTTC, better than S&L (though I like that one, too). When I do it again, I will be using it on its own, or alternating with S&L and/or Tony Horton's "Sculpt 5-6" from P90 Masters.
I would suggest doing it by itself, 3x a week, for at least a short time (5 workouts), to see what it does for you. You might like the results (and if not, you can always change it up before losing much ground).