As Sidney is limited to the purchase of Poser 7, I bought V4 "complete". I have never had Apollo, so I can only say that if this is "borrowed" from Anton's ideas, then I'm sorry I haven't jumped on the train then.
I don't want to compare with Sidney. I can't. I can only say that V4 impresses me a lot. The mesh is really improved (far from perfect, but I'd say at least twice as good asV3). Apart from a bizarre set of name morphs (Maria's lips, Conchita's eyes,...)the morphs are much clearer and well organised. It's easy to use them and see what happens.
The thing I was most afraid of were the eyes. Well, making them slightly larger and closing the upper eyelids a bit made them, for me, much better.
Here's a quick render. I'm not there yet, but, unfortunately perhaps for merchants, she's so easy to tweak than I'll only be buying a few top-quality skins I really like.