The CS suite is designed to dovetail into a management app called "Version Cue". It's designed for big organizations with multiple designers/artists working on the same project. It manages source files and graphics, so that everybody can remain in sync.
I don't know any more about version than that, since i'm the only graphics user at work. THere's no one to be in sync with.
Other than that, all the CS products are designed to work closer together than ever, which is the trend they've been following since Adobe bought Pagemaker from Aldus.
But PSCS is a solid upgrade. It rearranges the interface slightly to reduce the awkwardness that resulted from 7's "great leap forward"
That's the biggest change. It's not as much a leap from 7 to CS as it was from 6 to 7. I just wish they had implemented the pallet management features they included in inDesign CS. At last, I can see my working file again! But only in InDesign. Still palletes everywhere in PS and IL.