Is the Cyberpower Pure Sine AC regenerator a good buy?

Ok after a lot of research, it appears that Pure Sine Wave Battery back-up units only output the pure sine wave when not plugged-in.  The problem here is you need big a$$ batteries to power your rig for a reasonable amount of time.

If plugged in, the units can still output a pure sine wave but mixed with "filtered wall AC."

Can any of you "Battery-people" share your rigs so we can see how you're getting your pure sine wave AC?

What is the process called that ensures the output power is pure sine wave?

It doesn't regen when it's plugged in, unless you modify it.

IMHO not worth it. 

Disclaimer: I have Cyber Power (on PC and TV) AND PS PowerPlant

Hi @fuzztone yes you're right it for sure does not have enough power to keep a hifi rig running for long...but my plan was to keep it plugged into the wall, so that it is continuously generating its Pure AC sinewave.

Would the corresponding hifi equipment plugged in benefit from this?  Or will noise travel from the wall through the batteries into the hifi?  Why would  you not plug your hifi into this unit?

No. Not enough power for long enough.

Just a cheap UPS.

Good for desktop PC to allow save work and power down safely and VCR recording. Now days digital usually records to the cloud so no needy.

I would NOT plug my hifi into one.