Man, that's a toughie. Here is my personal list of plusses and minuses (SP?) for each.
Boot Camp / Muscle Endurance: Boot Camp has 8 total nosebleed cardio intervals about 1:15 minutes long each, with lower body, upper body and core intervals about the same length. Lotsa premixes within BC. Muscle Endurance is a workout that in all honesty I've never done, although some of the lifts look pretty cool. AND, the ab / core routine with med ball is one of my faves. Great bonus premix of BC and ME too.
HSTA has some my favorite step-blast cardio intervals ever. About 2:00 long each. Each of the five cardio blasts is also followed by legs and upper body. Music IMHO only so-so, and you have to get used to the song dialing down to a slower bpm between the cardio and leg work, which can get seriously annoying. Great premixes on this one. No abs / core - booger.
I-Max 2 / Cardio & Weights: IMax2 has some of my other absolute favorite step and interval blasts ever. The song for step/interval-blast #6 sticks in your head for hours, and it's a perfect match of song and drills. Blast #9 will make you cough up a lung, which is why I love it. Many others that also rock. Cardio & Weights for the most part is far too moderate in intensity for my taste, but, as with Muscle Endurance, it has one of my alltime favorite ab / core routines. Not so many leg presses as I recall in Cardio & Weights.
IMHO it's almost a coin-toss between HSTA and Boot Camp for high-octane circuit workouts. Much depends on whether you want step or floor cardio. If step - HSTA. If floor - Boot Camp.
HTH -
A-jock
