You have to watch for the low end ones, they are not well designed thermally and past the 15-30 minutes they are designed to power a small pc they could overheat the inverter. But the well known brands such as APC or tripplite will work fine.

Couple things to think about. Those consumer UPS's are the switching or offline type. This means they send power straight through and until the voltage is high or low enough to pass the thresholds they then switch over to battery. Depending on how good the filters and such are this still allows noise, spikes, surges, etc through.
Now there are online type, medical, data center, etc which have a bigger battery charger and always run the inverter off the battery and charge the battery from the input so there is no direct path and the battery acts as a big filter. You could buy one of these or look at ham radio folk who run a big 12v supply and power their radios from the battery. Look at the thread last week dealing with 12v lighting, this is how I'm doing my emergency lighting and gear, all 12v dc off a battery which is always charged. This eliminated the losses in the inverter as well as issues with the aproximated sine wave and noise and such due to offline ups's. My next step is to use a solar charge controller and solar panel to charge the battery and use the charge controllers low voltage disconnect to switch back to the line powered supply as needed.