I've worked with APC UPSs in a company a while back, but they had their servers hooked up to them. They were able to provide 20min of power in case of an outage, and the unit would initiate a regular shutdown of the servers before battery power ran out completely.
For my workstation or pcs I've never needed this. For one, because power outages are extremely rare where I live (maybe once every 5 years), and two, because I don't have pcs running 24/7. The most I can lose is a couple of hours of rendering.
And even if you had a longer outage, your pcs would still have to be shut off when the battery runs out.
What's your intended use-case?