As far as I can tell, the system seems pretty fair to me. If the songs are brought up at random, then it would be mighty difficult to play it. There is a bit of jumping around to start with, which is to be expected, but after while, the rankings seem to move up and down at a slower pace, which is more indicitive of where a song stands relative to it's peers. it's a good tool to judge public perception, which is quite different to a muso's point of view.

cheers, niteshift