Having just went through a power upgrade, I can provide my experience. I went from an old electrical panel and one 15amp line to having a new panel and three dedicated 20amp 12gauge Romex lines, good Siemens breakers, each placed as far away as possible, better grounding, and run to quality Audioquest outlets. I kept it as simple as possible after doing a lot of research prior.
My system didn't sound bad before, but it went up several levels after the upgrade. Noise floor dropped significantly, bass strength and definition improved, more detail comes through, and the whole system sounds more 'effortless'. It made a bigger difference than many components I've added and was significantly cheaper.