i have a close friend who is a co-promoter with a company manufacturing one of the best on-line UPSs in the country, Kaveri (Kaveri Powertronics - India's first DSP Controlled UPS).
from their background, since they were the first company in India to introduce the Truly Digital Online UPS System, they believe that owing to the very high switching frequency used in UPSs, the introduction of unwanted harmonics into audio is unavoidable.
consequently, they have been recommending CVTs for these applications (to me and other audio enthusiasts).
i myself am using a CVT for both audio and video (separate) devices (from a company called Bhurji, again recommended by them and referred to in a few other posts). only, there is no power backup in the case of an outage.
some of the senior members have suggested this may not be the best option, though, for various reasons.
to me, the jury is still out on this one.