Note series doesn't really have palm rejection - it prioritizes digitizer over touch so if you first touch screen with stylus (or move it close enough) all subsequent touches will be ignored. Now this is usually not enough since when drawing peoples tends to rest their hand first which lead to unwanted touches. That's why ArtFlow (disclosure: I'm lead developer) implements two separate features: pen only mode and palm rejection. Palm rejection uses touch point size and works really well on Note series (it has to be activated manually because some of devices return really erratic data from touch sensor leading to unexpected behaviour)