I'm in the anything-but-APC camp, after acquiring an assortment of APC UPSes in various ratings courtesy of Mr-Barakta's-Dad's former employer over the years, plus one that I paid real money for when I was a PSO with a prepayment electricity meter. They were all fine apart from the batteries, and one case of physical damage. The ones we put into service all eventually did the classic APC thing of shunting to battery to test the battery and thereby interrupting the power when it turned out that the battery wasn't up to it. Which it inevitably wouldn't be, because they'd all cook the batteries over the course of about three years. In my mind, a UPS has one job, and it isn't causing power outages. If the battery is shagged it should sound an alarm, switch to bypass mode and stay there, FFS.
(Similarly, the BHPC owns a small modern(ish) APC unit, which is utterly useless for the use-case of giving you enough time to feed the infernal combustion engine more petril if it conks out mid-race, on account of fussiness about voltage and/or frequency (I didn't have a meter to hand) causing it to run on battery until depleted and then shut down. For added lols, its sole means of communicating with the user is a single unmarked blinkenlight and a beeper, which is insufficient to determine that this is what it's doing without reference to the destructions. I've since molished a sensible redundant power supply for the Box of Winky Lights™ to avoid this problem.)
Anyway, a little later, also courtesy of Mr-Barakta's-Dad, we acquired a Chloride online UPS with a 3kVA rating, which was utterly bulletproof. The original batteries lasted years, as did the ones of half the capacity that I replaced them with. Its only weakness was a proprietary management interface that I couldn't find any specifications for, and being too heavy to lift without pyramid-building tactics.
These days we've got a now-discontinued VFI 1.5kVA rackmount thing that works well, albeit with ridiculous fan monitoring that made replacing the fans with something quieter an issue, and a smaller Salicru unit (chosen entirely on account of its dimensions) protecting the downstairs network stuff.
My conclusion is that you get what you pay for, and that online (dual conversion) UPSen are considerably better engineered than the offline type.
