The C stands for color and I believe the x stands for the SiFiIII chipset. The C is the standard color and the CX is the better accuracy chipset uint. I bought the 60CSX, it is amazing how accurate it is in the deep and under heavy canopy. I have been doing some geocaching to help me get familiar with my unit and have found it to be a great handheld unit. Especially since they released a new firmware that corrected the WAAS functionality and has made it even more accurate. When I say accurate I am getting it down to 6ft in the woods.The Garmins area a great unit and I suggest looking at this forum to get more info. http://forums.groundspeak.com/gc/

Hope this helps, Jeff