I tend to take the DxO ratings with a grain of salt too, but from what I've seen the current generation of EXMOR sensors from Sony and Nikon really do have about a stop of dynamic range advantage over the same generation of Canon sensors. That said, this is hardly reason for Canonites to get some kind of inferiority complex, dump their kit and trade for the dark side.
Extra dynamic range (smoother blacks at low ISO and maybe a bit less noise at high ISO) would be nice, but what kind of pictures we can obtain depends a lot more on the sort of lenses that are available (an area where Canon still has an advantage). Furthermore Canon and Nikon have swapped places in sensor quality several times over the years - and each time photographers seemed to produce great pictures from each system.
Body features are nice, but you choose a camera system for the lenses.