Don't know how much your budget is but spending more often pays off as in much longer time, you also have to be careful that the wattage of all equipment plugged into the UPS doesn't exceed the output wattage. Remember that even if mains power is supplied, all power used still goes through the UPS doesn't bypass it, count the wattage you would be using, can ONE input iec cope with all of this? Would you be running amps through it or just equipment that requires properly shutting down like a digital mixer/ethercon switches etc..., not that you want to incorrectly switch off an amp or things go bang. You could split the input power to equipment and use an automatic power selector (like a backup generator for a house does) when the main input goes dead it switches to the other input, although sometimes this switch isn't quick enough.