the power provided by most inexpensive UPSs is a horribly-misshapen, pseudo-sinewave, with very high harmonic content? Much worse power than you'll ever get from the POCO.
Be aware that during normal times (POCO lines are supplying power) many cheap UPSs just pass POCO power (via a relay) to their outputs and only cut in when there is a power failure. The only purpose these UPSs serve is to give a computer user a chance to save a file and then shut the computer down in an orderly fashion. The batteries will only last about 20 minutes. Thus this UPS is of no benefit in a high end audio system.
