IMHO, I like the $30 set more.
I prefer cheapo Steve's facesculpt as the collector's version looks a bit samey to a generic Ken doll head. I also like cheapo Steve's outfit compared to the collector's drab green outfit. But those damn molded on pants makes it a moot point. Maybe if I could find a spare Fashionista Ken body to transfer cheap Steve's head onto...
As for Wondy, it's mostly a choice between sculpt vs. articulation. The collector's version has an articualted MTM body, which is nice. However, the cheap Wondy has the all-new muscular female body buck, which is a far better fit for an amazon. It's really unlike any fashion doll body Mattel has put out since. Again, the collector's headsculpt is too doll-like. Cheapo's clothing is cheap, which is the only major downside I can see. But she does come with a sword!
Yeah, I really can't see me paying four times as much money for the collector's set when the standard 2-pack is just as good. For just about the same amount as the collector's version I can get the standard 2-pack AND Mr. Crystal Cavern King in OP's pic to play with my new Amazon princess.