Just upgraded to the SR (Shielded Round) 15/4 series. Very nice and a better more silky treble compared to the FLX16/2 I was using earlier. Needs a wee bit more bass though but since these cables are sponsored I'm not complaining
The SR15-4 consists of 4 X 15 LGC (long Grain Copper) awg wires and can be used for bi-wiring. When used for std setup 2 wire are combined into a 12 awg wire. Only downside I can think of is price and the size (diameter) of the cable. The large diameter makes it more difficult to route through tight areas.
http://www.audioquest.com/pdfs/custom_install/sr_series.pdf
