I own both varieties and honestly cannot tell the difference when using them (except visually, of course). Both receivers can be paired with up to six Unifying devices and have worked flawlessly for me so far. According to Logitech, there is a 'repairing' limit on the older models that should limit the number of pairing changes to 45 times. Since the official Logi website only offers the Pico, I assume that this is the more recent device and would therefore see no reason to buy the four franc more expensive and older Nano. Greetings David