I've noticed that, as well. Different formula and/or processing of hte plastics, I guess. The Plastruct plastic is a bit harder to cut and shape, overall, but I prefer it whenever I'm scratchbuilding a structure. Plus, the Plastruct plastics seem to hold hard details better, whereas the Evergreen tends to be a bit softer. Both have good and bad points is all I'm sayin' and it depends on my needs as to which I'll purchase.