This all depends on where you live, like where i live, in sweden, its very unneccessary since power surges does not happen. But if you are from a lesser developed country or a country with weird standards (USA) i should look into it. UPS stands for unlimited power supply, which basicly protects you from power outage.
actually electricity doesnt go out much but right now theres maintenance going on, getting small hiccups and outage for 2 mins.
so its first hour of using Sinewave inverter UPS, doing good job, hope it would be nice..