For most of the time, I did Legs and Back...it is a good workout, especially for the back and the leg stuff is just different (which can be good).
To help the legs stay strong (and get stronger) I did GS Legs on Tuesdays. Since it sounds like you already have been doing GS Legs, maybe do Leaner Legs or the other Cathe "leg only" workouts.
Towards the ends of the entire rotation, I became so sick of that workout because you do that one straight through whereas the others...you do for 3 weeks, break, then others for three weeks, break. Legs and back is every Friday! So, once I became super sick of it, I would put in Cathe's HSTA, do just the lower body part and add in the pull-ups from P90X legs and back. So, after each lower body segment from HSTA, I'd pause and do my pull-ups, then do the next HSTA leg segment, etc. Made for a KICK ASS workout!!! Then AbX.
HTH!!!