Fremer uses two power plants, although he used conditioners until someone completely screwed his incoming power power supply. In his recent article in Stereohile he says the regenerator vs conditioner issue is suspended until he gets his power fixed.
I’ve used a regenerator, conditioners and universal power supplies.
I use UPS for computer and servers. Most consumer versions will not have enough headroom supply for decent audio, unless it is very undemanding. They are very cheap and ideal for servers and computers, but do need replacing every few years.
In Europe we have had a legally enforceable code for the quality of the power supply, going back to 1980. In the UK we also have a National Grid, don’t know about the rest of Europe, so we are not prey to local suppliers.
My basic understanding is that the basic issue is that high impedance supply will result in large voltage swings if the draw is heavy. So this will depend on the hifi equipment you are using and how demanding it is. The EU code includes a maximum impedance rating and in the UK the impedance is generally better than the legal requirement.
The other issue is noise: (a) borne on the mains, (b) from EMI/RFI, and © from components feeding into your mains distribution unit.
Wiring systems also differ. In the UK we use ring mains, apparently illegal in the USA. Of course standard voltages also differ depending where you live.
The iFi Power station seems to be the most popular and effective budget device with full cross-contamination isolation, so I bought one for my office.
When I changed from highly demanding amplifiers to Class D, I changed from a regenerator to a mains conditioner. My regenerator had transformer hum. I went for the Shunyata Venom, in part due to the excellent build quality.
My circumstances only serve as an example, and with different amplifiers and different quality mains I regeneration might be needed.
Wondering how @Arenith is getting along on this and perhaps details of his system can be provided.