This deal is still valid so I am reposting it since it was moved to Deal Talk
There are 2 APC UPSs on sale both are Pure Sinewave but they are line interactive.
This means that the UPS when on Battery will output pure sinewave but when it is still functioning off your street electricity there can be some voltage that is dirty that gets through.
If you need pure sinewave at all times then you want to go with a higher priced model that runs in Online Mode not Line Interactive Mode.. Online Mode UPSs like the Smart UPS Series that can cost twice the price use a internal voltage conversion so that the power out of the UPS is always perfect Pure Sinewave. Unfortunately they do cost much more
Also you should make sure that your UPS won't trip your Arc Fault or GFCI Circuit Breakers. To understand this you really need to go to the manufacturer's website and learn more about that but this can often happen when the circuit is overloaded even if the UPS is functioning correctly.