The difference between a 256 Kbps file and a high res version of a good recording is night and day, for me showing up most obviously in cymbals and drums.
I usually do not go deep into these discussions as there are too much religious feeling about their positions on both side of the spectrum.
But comparing a 256kbps file to uncompressed 24 bit / above 96khz sound files, are mostly agreed that there is an audible difference. The question has usually been if 16 bit/44 kHz is perceivable different from an audiofile played in 24 bit/ 96 kHz ( or anything above the CD-reference).
Usually the argument comes down to the sampling frequency used, as you would need a silent anechoic chamber to be able to enjoy the full dynamic range of 16 bit. In the dbSPL range with 0 db at 20 μPa, the background noise in a silent room are around 25 dbSPL, and you would not and should not be exposed to sound above around 120dbSPL. If you turn up your sound system to a level where peak is at where you will risk damaging hearing, the lowest sound that a 16 bit system can playback will still be at background noise level.
Now there is the effect of sampling frequency. There are theories which state that a human are still able to perceive frequencies above 20kHz even if the ear are unable to hear it. But there are more mundane technical reasons why higher sampling frequencies are possible to discern. The output from an DAC is theoretically squares, but square waves are impossible to create in the real world. This creates amplitude distortions. Usually this is fixed by a low pass filter at half the sampling frequency (the Nyquist frequency). Without it you will get a so called aliasing effect. Further on your loudspeakers will also naturally be a low pass filter, as in a electric cable, it is definitely impossible to create perfect square waves from an moving system as a speaker. The movement at the beginning of a wave will create over harmonics as high as the element is able to swing.
But no matter what your system is constructed from, the last and most effective signal processor is your brain, and most of the artifacts you will hear are created there.