That's an impossible question to answer really. Both brands have large ranges to suit different budgets. QEDs budget speaker cable may be better than IXOS's, however IXOS's high-end optical cable may be better than QED's (hypothetically speaking of course). It's best to decide on your budget for whichever cables you need then find some reviews or try out the cables yourself.
lee37: QED QUNEX 2 INTERCONNECT £13 QED PERFORMANCE OPTICAL DIGITAL LEAD £30 QED QUNEX PERFORMANCE HDMI-P HDMI £50 QED PERFORMANCE COAXIAL DIGITAL LEAD £25 QED XT350 SPEAKER CABLE £13 metre with QED AIRLOC PROFESSIONAL-FIT 4MM BANANA PLUG £5 each