I've used Rapture (original) for many years, and I still find some of it's sounds to be the "go to" sounds for my work. For example, the Moog Pedal Lead and Lyle Mays patches are particular favorites of mine, and there are others. I prefer it to Dimension Pro, although I used to use that a lot and still occasionally do. Even though I have some other synth VST's, such as AAS' Analog Synth, I think Rapture has a lot of potential. I've just downloaded Rapture Session, and not sure how much I like it--for one thing, patches seem to take longer to load, very annoying. But having everything, Dim Pro, Rapture legacy, with some Pro patches is a nice touch.
I don't do much sound design, more a preset user, but I have fiddled with Dim Pro at this, and both instruments do have some good tweakability, although Dim Pro's interface was not really to my liking. I'm mulling over Rapture Pro, but not sure it's worth it to me. Need more time to sample Session first.