I can't answer the cost question, but I can tell you from personal experience about the difference in the Ref and Syn speakers. Long story short:
I auditioned five sets of speakers with several of my own CDs, several times over the course of a couple of weeks, all at one shop. I was never told whichs speakers I was listening to; I ranked them by number.
The Klipsch Synergy bookshelfs and surrounds were in the lineup. They consistently beat the others (beat three brand-names hands down; it came down to the Klipsch and some Energys, but only because the Energys also beat the other three by a country mile).
Then the store received their Reference series. So we did another compare. Let me just say that the Reference beat the Synergys by as much, if not more, than the Synergys has beaten the worst of the lot in my previous tests. There is actually that much difference in quality. It is twice the speaker for not a whole lot more money.
The same is true with the surrounds: I took the Synergys for side-surrounds, because the Reference surrounds are almost as big as the bookshelf units, but then a month later I took 'em back and switched to the Reference. The sound is just too worth it!
Now, some may prefer the floor models, especially since they are the same price. I can't handle floor models in my place, so I didn't even compare 'em. But most everyone feels that they are even better than the bookshelfs, and so they should be.
As for subwoofers, I opted for the KSW-12 over the 10 incher: $100 difference in price, and better than twice the quality and output even after just a 5-second listen. I would guess the 15s are that much better again. ... Mike
