Considering a UV or ozone add-on, anyone running one long term

I've been liquid-chlorine-only for years and happy with it, but a neighbor just put in a UV system and swears his FC holds steadier between doses and he's dropped his CYA target a bit as a result. I'm skeptical of anything that smells like a gadget fix for what's really just a dosing discipline problem, but I'll admit the idea of knocking down chloramines and some of the resistant bugs without adding more chlorine has some real chemistry behind it, not just marketing.

Anyone actually run UV or ozone on a plain gunite pool for a full season or two? What did it actually change on your test numbers, not just how the water felt. Mostly curious whether it let you run FC/CYA leaner and still sleep at night, or whether it ended up being another thing to maintain for marginal benefit. Not looking to spend money chasing a problem I don't have.