Is an isolation transformer better than a power conditioner?

What about a high quality UPS? That cleans up pretty much everything in terms of AC line noise from other electrical equipment, voltage transients, line distortion (if you have it). It puts out perfect sine wave power. Plus, it would be a lot cheaper than some of the approaches mentioned such as the Shunyata Triton, or expensive rewiring of the last inch of electrical service.

I would note that a UPS does not typically provide galvanic isolation, and only secondary surge suppression.

Now that my new dedicated AC line is installed, I am deciding on replacing or combining my very pricey Shunyata PC with a PS Audio regenerator.

The difference between running my mono blocks directly into the new line or connecting to the Shunyata that is plugged into AC is huge. I have re-evaluated my impressions of the Shunyata. The sound of the Shunyata with the new AC is spectacular.

But audiophilia moves my to try putting in a PS Audio P12. 
Anyone have experience with the PS Audio?
 

I use a PS Audio P20 for the last few years and have found it to be a great addition to my kit.  Larger sound stage, more micro detail, lower noise, also, because of the low impedance, there is more openness on loud dynamic passages.  I am using Auidioquest Hurricane power cords throughout my system and have a dedicated 20 AMP circuit to the P20.  From what I understand you can demo any of the PS stuff for 30 days and send it back if you don't like it.  I have done A/B with and without the P20 and definitely prefer the P20.  

I took Charles advice a while back and now run Equitech on 4 systems. Best audio advice I ever got. Huge improvement IMO. (I had tried Shunyata and PS regenerators), There is a reason so many of the big boys use Equitech.

I have used isolation transformers and preferred the sound without. The sound was less alive. I use a PS regenerator and prefer that to without. Have fairly typical power usually reading about 2.7% THD.