Amazing! This is about the APC Back-UPS Pro 900! I bought it in 2011 and even after 15 years it works PERFECTLY! Of course, I have changed the batteries a few times since after some years they wear out... What really impressed me is that I tried to see how long the battery would last (it's actually two batteries) with the devices I had connected, when I intentionally cut the power... and while it showed me that I still had almost half an hour left (if I remember correctly, 27 minutes), it actually lasted ONE AND A HALF HOURS exactly, that is, 90 minutes!!! Of course, the total load was almost 1/5, that is, not even half of half! Extremely satisfied! Whenever I needed it, it never let me down!

It never worked, as soon as I got it, it started to smell excessively and made various noises. I unplugged it after 5 minutes, plugged it back in and it made a loud bang. I unplugged it because I got scared. I called the company I bought it from and they referred me to APC service, I sent photos and a description, no response. Thank you anyway for the support, never again APC. The UPS is in its box unused.

As long as it works, it's perfect. Long battery life (it takes two), good accompanying software, but...
An expensive UPS like this, from such a reliable company as APC, I would expect to last more than 5 years.
Unfortunately, at the five-year mark it stopped working and APC's service told me it cannot be repaired.

Very good, silent, and reliable. In short, you are sure that you have a UPS, and you don't think you do.

Very good build quality, silent, immediate access to all necessary information from the panel, easy battery replacement.

Like all the APC UPS units I have purchased in the past, it works perfectly. The connection to the computer via the included software is equally flawless. It shuts down your computer when the power goes out and after the preset time.

It made an annoying sound every 4 seconds and because I had it in a room it was very annoying, I tried to connect it to other sockets in the house and it did the same thing again....
In the end, a refund was made.

After 2 years of continuous operation, it has proven to be reliable every time it was needed (version 1200VA 720W). I recommend it.

I have had it for a year and a half and it has saved my PC three times, I easily managed to shut it down after a power outage. APC is the best for protection!

It was purchased a few days ago. At first, I noticed a linear buzzing sound that would intermittently occur every 4 seconds. Although it wasn't unbearable, I decided to contact APC. Excellent customer service! The representative for Greece called me IMMEDIATELY and asked for complete details for replacement. However, by changing the outlet (I had temporarily placed it in a power strip only for charging its batteries), the problem disappeared completely and I cancelled the replacement.

POSITIVES: Its batteries (2 pieces connected to a carrier) are replaced by you with a single movement (you took out - you put in). Quiet and sturdy with a clear screen that shows the load the machine is receiving at any given moment.

NEGATIVES: None

Highly recommended ALSO due to the incredible after-sales service!

Just now I opened it and I have it in my office, I will do a more serious evaluation in due time, just to note that because I have it on my desk, it makes a noise constantly, probably the fan, as annoying as possible when you don't wear headphones for example... if it was a meter away from the desk, or below the desk, I wouldn't have any issues I think, I will write again within the week.

The sound comes from the front, if you put it high or low, a meter is fine, almost silent.

Doing a stress test on the computer recently, I noticed that the watts it can provide until the battery starts to drain is 540, then it starts to consume battery until it shuts down. I consider 540 watts quite enough for the average user, with a monitor, a mid-range computer, and a small speaker system. In my case, I exceeded that because I used both the processor and the graphics card at 100% for a long time with fans at maximum (3x120mm and 2x140mm). Under normal conditions, I don't even reach 300 watts.

Very good UPS, reliable, with a display that shows the load of the UPS and how long it can hold. Additionally, it comes with an excellent and user-friendly PC application.

I have had this particular UPS for over four years. I use a much older model in the office where we have frequent voltage drops or power outages.
Simply put, the word UPS is synonymous with APC in everything: Money, noise, reliability, functionality, service, etc.

I use it on a Mac Pro. In standby mode, it is completely silent. In battery mode, you can hear the fan, which activates immediately after a power outage if there is a load on the UPS. Also, when it operates on its batteries, the output does not have a clean sine wave (the waveform is simply squared), causing the power supply of the Mac Pro to make a buzzing noise (this sound creates insecurity that something is not right with the input voltage to the computer, even though it is 230 volts), so you have to turn it off immediately to avoid any damage.

I don't have this buzzing noise in other devices' power supplies.

On the positive side, it has a display with full indication of operating status (input voltage, output voltage, frequency, battery level, remaining time, etc.).

Also, in the computer settings, I have full control of the UPS without having to install any software or drivers. And all this is simply done with the USB cable provided by the company with the purchase of the UPS.

I have had it for 2 years. I had no issues at all. It made me realize how unstable the electricity is in the house. It goes out 2-3 times a week and almost always when it rains. I haven't had to change the battery yet based on the test the company's software does.

Update after 4 years (17/04/2021):
I have changed the battery once after 3 years. Everything is fine, no issues. Anyway, it says that the battery needs to be changed every 2-3 years, but 55€ every 2-3 years is nothing compared to the cost of your equipment breaking down.

Excellent UPS with APC warranty. It lasts for a sufficient amount of time for the load I have given it (monitor, computer, NAS, IP phone, router, switch). Its batteries are also easily replaceable.