People have personal and subjective opinions about the sonic effects of different kinds of AC power products on their audio systems. I think the only intellectually honest thing that can be said is that there is no way to tell in advance what will be the sonic effects of power regeneration versus isolation transformer versus balanced power versus passive noise suppression versus battery power on a particular audio system as perceived by a particular audiophile's ears.
No rule of general applicability can be formulated. Which power device, if any, is "best" will be very idiosyncratic and will depend on each audiophile's particular mains power voltage stability and variance situation, ambient EMI environment, audio system components and personal sonic preferences.
In setting up a new audio system I assumed that I wanted either a PS Audio regenerator or an isolation transformer/balanced power device for my turntable power supply, phono stage and line stage preamplifier. I compared a PS Audio regenerator to an Equi-Tech device on a friend's familiar system. See
https://whatsbestforum.com/threads/equi-tech-2rq-versus-ps-audio-p10.30215/
The sonic effects of each of these devices on my friend's system were very audibly different. Which sonic effects were "correct"?
That comparison experience left me so perplexed that I have decided to put together my new system, at least initially, with no AC power devices at all.