I did a PH/MIS rotation (three days a week, alternating the workouts) for about 4 weeks before going on to PS for 3 weeks, then Slow and Heavy for two weeks before my current CTX rotation. I feel that the weight rotation of PH, MIS, PS, SH gives a workout of increasing intensity. Then I take the weight training intensity down a bit with CTX, which ups my cardio. I wouldn't necessarily recommend CTX if you are 50 pounds overweight, as the cardio is pretty high impact (I modify about half of it) and it can be stressful to the joints.
So, my suggestion would be to move on to PS, then to SH (for a short period of time) if the slow and heavy concept interests you.