Nancy,
I only have Banish Fat, Boost Metabolism which I did for the first time last week and loved it. This is my first Jillian. I got it because I read all the rave reviews (especially Jeanne Marie's) and felt I had to get it. I've watched Jillian Michaels on the Biggest Loser and am not a big fan of her or her style but she wasn't that way at all on BFBM. She was quite encouraging and actually made me work harder. BFBM was an all cardio workout clocking in at 54 minutes. Here is some of what I posted in my checkin:
It's not as tough as an IMAX but you get out of it what you put into it. There are 7 circuits where you go through each circuit twice. One of them is a core circuit which has plank work, supermans, toe touches lowering feet 3" from the ground, mountain climbers and walking pushups (spider pushups). This is totally basic choregraphy (not my usual favorite). Reminded me somewhat of P90X Plyo X and Kenpo X. Jillian was very encouraging and actually made me work a little harder. She wasn't like her usual persona in Biggest Loser. There was lots of kickboxing in it: fan kicks, crescent kicks, side kicks, back kicks, a punch combo (only bad part she did it to one side twice but I switched and did the other side), upper cuts, punches to ceiling, squat kicks. Also lots of plyo stuff: plie jacks, squat jumps, plie jumps, jump rope, 180 jumps. Then there was the cross-country, standing mountain climbers (high jog with alternating arms), butt kicks, skaters, burpees. Also lots of standing core work. There was pretty much no rest between circuits. Overall, a great workout in under an hour.
Jillian has two background exercisers. One shows the more advanced version and the other shoes easier modifications. Jillian does the workout but also walks around to instruct.
Hopefully, that will help with your decision. I also plan on getting 30 Day Shred and No More Trouble Zones.
Marcy