I've been using them for over a decade now.
I have my main fileserver and the DMZ on one and, since I went to FTTP, I also have an old one on the fibre modem and the main WiFi hub. Everything else except laptops just drops with the power. Linux is pretty well behaved during those outages due to the journalling filesystem. I don't use Windows enough to know how reliable its filesystem is to outages. Fortunately in the UK we don't get very many.

The first UPS I had was taken out by a nearby lighting strike. It didn't entirely protect the machines, but it probably helped. It was a cheap generic, but I've since gone to APC. Whether they're better proof against lightning I can't say.

The machines I keep ion the UPS are fairly low power machines ... fanless ITX server and Raspberry Pi DMZ, so if/when the UPS gets called upon, it'll run those machines for a couple of hours. Most UPS setups are intended only to give time for an orderly shutdown.

Generally the UPS has an interface so that the PC can monitor the situation and shut dwon in good order when the battery is getting low. My first UPS was non-standard and that didn't work with Linux, so I just did without it. Later installations I simply haven't bothered.

Jazz relative beginner, starting at a much older age than was helpful.
AVL:MXE Linux; Windows 11
BIAB2025 Audiophile, a bunch of other software.
Kawai MP6, Ui24R, Focusrite Saffire Pro40 and Scarletts
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