OH MY, this so reminds me of back in the day when the discussion was which was harder, Imax (there was only one at the time), Intense Moves, Maximum Intensity Cardio, or BodyMax.
The plethora of choices with which one could answer this question in 2014 was beyond imagining back in 1998/99!!
Just interrupting this thread with a nostalgic moment.
Carry on!