One important aspect to keep in mind:
Always remember to keep things into perspective when individuals use terminologies such as:
HUGE difference, blows it out of the water, knock your socks off, orbits into space, leaves it in the dust, etc. Some changes to the ear has an impact on some to over-inflate, dramatize, or get over emotional in statements made. Often, even subtle difference can cause this effect in individuals. I've come across this more frequently than not.
Even though Klipsch F-series is more budget, it holds up very well. Many have been very impressed with their performance, especially in ratio to price. The RF-series upgrades you to better cabinets, drivers, (bulid-quality) etc. It's really best to listen to each and decide at what price point your ears is willing to spend to justify what it hears. If you can, try and listen to each on the same equip, even if you have to bring your own so you really get an idea what you are hearing, say on your favorite CD you are very familiar with. If the differences are great enough to you to justify paying more for what you want, or you may find it's not enough to justify paying more. A good way to start is to listen with your own hears and not someone elses since the final enjoyment is what you like to what point! Good Luck.