I pretty much agree. Imax is tougher, but dated. Imax2 is still tough enough to be impressive, has great premixes and is more fun. If you can't get both, get Imax2.
Imax is more similar to Gin Miller, because the moves are so simple. I still use Gin Miller's Intense Moves sometimes, but I do hate that hat she is wearing. Nevertheless, it is a great workout too. In fact, it is the only nonCathe I still own.