I recently bought the 800 model of the 480 W UPS with the purpose of connecting it to protect my Synology NAS, replacing a small cheap Eaton 5E UPS that I would use elsewhere. Therefore, I had low power requirements and didn't need a larger UPS. First, I will mention the positives of the UPS, which in theory were so many that, combined with the positive reviews, made me buy it almost excited:
(+) of course, the price for the 480 Watts, which is truly value for money, especially considering its other features that bring it ahead of the competition at this price.
(+) good build quality, sturdy
(+) small dimensions ideal for fitting in a small space like a shelf without being obtrusive (exactly what I was looking for to place next to my NAS). Very lightweight for a UPS.
(+) silent operation, if it didn't have the blue screen and the button, you wouldn't even notice it's working. It has low power requirements and that's why it doesn't have a fan. In short, it is a small and quiet device that can easily be "hidden" somewhere without causing any disturbance.
(+) bright LCD screen that displays essential information about the voltage, battery charge, etc. It's not just a black box, it informs you about all the above. A rare feature for such a low price.
(+) simple and safe operation with a central button for muting the sound and turning off the UPS
(+) AVR support, meaning automatic voltage regulation for even greater protection of devices
(+) Schuko sockets
(+) USB port for data to the computer, etc.
(+) protection for the home telephone network, e.g., the router
(+) the manufacturing company (BlueWalker GmbH) is a well-known German company and not some unknown Chinese company
(+) good UPS support with a variety of programs and applications for all types of operating systems and with many customization options regardless of the environment (corporate, home, etc.).
(+) in cases of two power outages, it worked immediately, as expected (almost as expected - I will mention below), keeping the devices on until I turned them off.
(+) I didn't notice any smell or excessive heat development, but I haven't used it for a long time.
Now let's move on to the negatives, which were a big disappointment for me and brought me back down to earth because, in reality, you get what you pay for:
(-) The biggest negative for me, and actually a deal breaker, was the USB port functionality and its very difficult (impossible for me) recognition by the NAS or computer. On the product page on PowerWalker, it specifically states that the USB port has HID support, which allows easy and direct communication with any operating system. Oh no! I had a problem with both my Synology NAS and computers with Windows. The main reason I bought it was to protect my NAS and give it a shutdown command when the power is cut off. Well, the NAS couldn't recognize it as a UPS no matter what, while until recently it worked perfectly fine with the Eaton UPS without any issues. It did recognize that a device (referring to some unrelated Chinese company, probably the manufacturer of the USB controller) was connected to the USB, but it didn't recognize it as a UPS. I followed some instructions on the site and on the internet, resorting to using the terminal, but I didn't get anywhere. Maybe if I had programming knowledge, I could have succeeded. The UPS may be defective, I don't think (I found elsewhere on the internet that it is a bit difficult in this field). Anyway, I decided to use it for my office computer since the 480 watts were more than enough. Still the same, Windows 10 recognized the device, but it was unknown to them! I downloaded all the programs available from the company's website, most of them were aimed at corporate environments, only one, WinPower, was aimed at regular users, but none of them solved the problem or recognized the UPS. I should mention that none of the other two companies, APC Powerhute or Eaton UPS Companion, had the same variety of software as PowerWalker for their UPS!!! So since I couldn't use it for the reason I bought it, which was for the automatic shutdown of my NAS or computer, I connected it to another computer that is not constantly on for 24 hours.
(-) The blue LCD screen is nice and bright, but there is no option to turn it off to avoid annoyance! They thought of giving the option to mute the power outage alarm, but they didn't do it for the screen, at least to turn off by itself after a certain time. If the UPS is in a bedroom, it will annoy you as the screen is particularly bright.
(-) Short power cable. Yes, you can use an extension cord, but compared to the other two UPS (APC, Eaton), it is shorter and also not detachable, so you can't use your own. It's a small inconvenience though...
(-) The 2 Schuko sockets seem few and I would like at least one to protect only from overvoltage.
(-) The Greek channel on YouTube "Hardware Busters" has done a detailed review of the UPS internals and they don't speak highly of its AVR function.
These are my main points, I started with a lot of enthusiasm for the capabilities and price of the UPS and ended up using it for a computer in my office that is not constantly on, so as not to waste it and use a bulkier APC UPS for my NAS. So, three stars from me, a good product for the money, especially if you just need something to keep your devices on in case of a power outage, but not so reliable, especially regarding the USB port and HID Support.