Lets see C6Pro...hmm.
Will not import anything you make in XDresser. You need a work around
Will not import anything if the word runtime is anywhere in you directory path other then the real runtime as in "myruntimes/People/V4/runtime"
Lack of support and or countless problems inporting pz3's created in poser 7
Expectation that Transposer 2 would come with p6, because transposer came with C5.
If you choose a large scene items come in different scales.
Dual monitors was broke in C5 Mac, still broke in C6Pro Mac (no work around)
You can't pose eyes for V3 (not sure about other characters) in C6Pro.
Many newer products-character sets use shaders. They are lost during import and you have to recreate them yourself. Some people bought certain items because they came with shaders and are disappointed that they might have wasted money on that purchase.
yadda, yadda, yadda...

Where Daz screwed up was they didn't test it correctly or didn't have enough beta testers. Plus there major mistake in my mind was they built this thing up in their pre-release publicity with their sneak peaks, uTube videos, etc to the point of mad frenzy....user expectations were higher then a kite. When the kite, fell and hit the ground, those same users are using the same mentality of a mad frenzy....Over expectations created by Daz, is coming back to bite them. In hindsight, they probably would have been better off with a soft launch. Sort things out, then make a bunch of noise.

Gary

"Those who lose themselves in a passion lose less than those who lose their passion"