Thanks for the feedback.

My main concern though was if there were any buzzing/whining/electronic noise. Since I would place it in a very quiet environment (<20db) I would certainly hear those, even more when the computer is turned off.

I need a dead silent UPS. 550W would be enough. The only sources of noise from my computer are 3 Noctua NF-A14 ULN rotating at 650 RPM and a NF-A15 PWM, and if it weren't for those there would be absolutely no sound in my room. Of course I mean when there is no power outage, I don't care how ridicul...