There is no reason why you couldn't use a power strip with a UPS, as long as it doesn't have the extra circuity to "clean" the line noise. You just want a basic power strip, nothing fancy.
I have used them for years at many different locations and not one problem ever.
*edit, obviously, you don't want to overload the UPS, so pay attention to the wattage of each device!
Also, pure sine wave vs simulated sine wave don't really matter that much for consumers, either are almost certainly better than your home wiring output. All PSUs created today can deal with either source just fine.