I auditioned the DC6T and the RX6.
To my ear the RX6 was well balanced and I prefered it to the B&W 684, which seemed a bit too warm and base heavy. The DC6T's had noticably more detail, a wider sound stage and more controlled bass, but I found the mid range a bit too distracting for the music I was listening too (guitar/rock). I'm now looking at getting the standmount PMC TB2i, which improved on the qualities I liked in the DC6T's and a midrange better suited to my music.