I was very impressed. I think they suffered slightly from being played after the Blades, as you would expect. It might have been better for the R-series to be demonstrated first, followed by the Blades. After the Blades I could definitely hear the extra cabinet colouration of the R-series, but this is by no means a criticism. For their price and, when you think how expensive the Blades are, the R-series sounding so impressive is testament to what KEF has achieved with them.
Although I am normally a stand-mount lover, I actually thought the floorstanders (R500?) sounded substantially better than the R300.
Only thing I would say is that they were some way from boundaries and still produced huge bass. These speakers might be a bit too much in a lot of modern rooms.
What did you think?