I am no UPS expert, but I have had 3 in the last 12 years now. My first was an APC SmartUPS which the battery died after about 3 years, it was very costly to replace so I bought a new APC BackUPS instead, which was a
APC Back-UPS BK650EI 230V that served me well for the last 10 years with the spec in sig for the most part of it.
I would say this should be able to run two very low end PC's, but it depends how much power they use of course, and if they just needed enough time to shut down safely.
I have however, just replaced the one I mention above with a higher rated unit which is this one
APC Back-UPS Pro 900VA 230V I have only had it a week and so far I am happy with it apart from a very strange noise that I hear every 5 seconds from it (a bit like a very brief "Hum"). My office is very quiet though so if this is a common issue with this type of UPS then most people wouldn't hear it I am sure. I have contacted APC about it..
Having said that, and although it is hard to judge after a week of use I do like the UPS so far (it also looks amazing compared to my old units). The display on the front gives lots of information about remaining running time, wattage etc. The supplied software also gives you lots of information and apparently my system is only drawing 135w idle at the moment and has an approximate 45 min run time on the battery.
