I'm glad I pre-ordered them all. I may never use Stretch Max (it didn't appeal to me at all on previewing), but I still paid a good price for the others. I might end up selling IMAX 3 and Hardcore Extreme on Ebay, but I think I'd get a return on them.
I wouldn't be happy with some of them if I had paid full price, because of some sound issues (and some really bad/choppy editing of the IMAX3 "step only" premix).