I bought a pair of Klipsch RF-3 off a craigslist ad, got a great deal. I have to say that they are very high quality for the little money I paid.
They have a "forward" sound, rather aggressive. I suppose you'd expect that from a Klipsch speaker. That might be the price one has to pay for very high efficiency from a relatively small system. They're advertised as 98dB efficient, but that's an 'in-room' measurement, so I suspect it's really more like 95dB/1w@1m anechoic. That's still a lot of sound out for a little bit of amp power in.
Dynamics from these speakers are great -- The piano on Bill Evans Trio "Waltz for Debby" SACD sounds very expressive. There's a big, wide gradation from soft to loud, with no 'mud.' Drums are expressive and dynamic too. Check out the way Paul Motian's drum solo builds and swells on Milestones. Very exciting, almost like real life.
The bass is really impressive. These speakers do go low. Low notes on a string bass are reproduced with nice authority, especially considering the relatively small enclosure. The two 8" woofers in the ported 'tower' enclosure do a very good job.
The RF-3's throw out a lot of midrange detail, lots of low-level nuances come through loud and clear. However, there is some harshness. There seems to be a peak or slight distortion in the upper mids. Strings can be a bit shrill. Human voice can be sibilant ("s" and "t" sounds seem exaggerated). There's an electronic edge to the mids and highs. It's not any worse than other mid-priced 2-ways I've heard, but it's there, and it's annoying to me. Maybe better quality capacitors in the crossover will fix that. I would not use the adjective "sweet" to describe the mid or high frequencies from this speaker.
Also, there's a bit of an "aaaaaaaeeeeehhhhhh" horn coloration that can get tiresome after a while. Not nearly as bad as the Klipsch Heresy speakers I heard a while ago, but it's there. I need to see if I can tame that by damping the driver baskets and cabinet walls.
My reference speakers (that I've been listening to for nearly twenty years) are Tannoy T185 Dorset, from about 1982. That's a 2-way horn speaker as well, but of an entirely different character. The T185 is more polite and 'laid-back,' while not as efficient (91dB/1w@1m). What the T185's do well is texture and palpability. Things can sound very natural and organic when driven by triodes. The RF-3's always sound a bit metallic by comparison, but low-level details are more apparent. I think it's ultimately a taste thing, but I find myself switching back to the T185's on a regular basis. On the other hand, I do love the excitement I get from the RF-3's, even when driven with my little push-pull 2A3 amp (6 watts per channel).
At some point I need to try the RF-3's with a good quality solid state amp, to see if that controls them better. But I don't own a SS amp at the moment. I may be able to try a Sansui TU-719. If I get to that, I'll report back, in the hope that someone might find all of this useful.