I am one of the guys that dont even trust my own hearing memory. Time lag, gear differences, raising heart rate from moving heavy gears.. Those things always make me skeptical. A/B in the same system with minimal time lag is what I trust.
A/B with minimal time lag is most of the time carried in a very uncontrolled and biased way and needs long and statistically valid evaluaitions. Surely in this hobby we are the defendant, the layer, the jury and the judge, we always pick what we prefer, idependently of method.
I am a believer in long and repeated evaluations, with all the risks that this process carries, athough I sometimes do A/B with digital acessories or tweaks that I am sure will not change the sound level.