Agree kay OJ88. Kahit papaano yung mga cheapie 500W kuno AVRs for PC eh me boost and buck function naman. Kaya lang, napaka-limited nga lang as it will have finite switchover points, like as mentioned mga 3-4 points lang. Kaya lang, on its own usually kaya naman ng PC power supply yung mains fluctuations. Speaking of power supplies, yung mga newer APFC power supplies hindi siya compatible sa mga standby or backup UPS. Kelangan nito eh yung online UPS na. Aside from the technical differences, medyo malayo rin ang price difference between the two.