Hi! I don't have Step Jam, so I can't comment on that.
The hi-lo of MIC, from what I remember (only did it one or two times) is very simple, high impact stuff. Grape vines, side steps, scoops, L-steps and step turns for the low section; medium secdtion you do like a boxer's shuffle type move, lunges to the side (jumping) with very basic arm movements, circle jacks; high section adds leaps to the side, lots more jacks, push-pull jumps, twists, plyo-jacks, airborn jumps, jumping knees upp (singles, doubles), up-over (jumping as you cross your knees over), jumping insoles---I think you get the idea. Ugh, I just don't enjoy this at all! It is EXTREMELY intense, and Cathe seems like she's having a great time, but if you like choreography, you won't like this!
If you have a DVD player, MIC comes on the Rhythmic Step + DVD, with RS and Interval Max. The advantage is that you can skip the hi-lo if you don't like it. I wouldn't call the step choreography too complex either, but having them all on one DVD is great for makingyou own combos! Well worth it.
Wendy