I owned these speakers for about 4 years and tried them with a plethora of different types of amps.
The one caveat I would have to say about these speakers is that you need to be very careful what sort of gear you pair them, especially the amplifier. Pair it with the right amp, and these speakers can sing, pair them with the wrong amp and they become a harsh, bright, painfully fatiguing mess.
For example, I hooked these up to a Wyred 4 Sound STP-500 (a very laid, rolled off amp) and they RS6 sounded amazing. I then tried them with an Exposure 3010S2 (a rather aggressive amp) and I would need to leave the room after 3 songs. I had the same results running the RS6 with a Rotel amp, not surprisingly.
For those of you who own tube amps. the RS6 is a good bet. At around 91db sensitivity, they are remarkably easy to drive, and will play stupidly loud. In the right room they probably reach down into the low 30's as well, so no need for a subwoofer with these.
The build quality of the RS6 is excellent - very solid speakers, and heavy too. They definitely pass the knock test. The C-CAM (ceramic) drivers are pretty cool, but be sure to sure to keep the grills on if you have small kids about. The will scratch or dent very easily.
Now that the RS line has be superceeded by the newer RX line, the RS are getting harder to find, but the good news is that (if you can find them) they can be had for a bargain. All in all, pretty darned good speakers, and a good value on the used market.