Excellent but...
It has a little fan... It's not unbearable if you have it in a room for use with a computer where you sleep as well... I turn it off at night because I can't stand the noise. It's not extremely loud but it's enough to not let you sleep peacefully. That's why 4 stars.

After the 3KVA Legrand UPS I bought for the electronics of a heating control installation, I was looking for a reputable UPS for a computer installation. I suggest avoiding non-branded or cheap Chinese brands, my experience with them has been very bad. The features I wanted were line interactive, providing protection against over/under voltage and surges, easy battery replacement, and a display showing basic status information. Although the devices I wanted to protect (a laptop, a low-power desktop, a monitor, a router, and a small NAS with 3 drives) don't consume more than 80W in total, I wanted a UPS around 1.5KVA (1000W) for good battery autonomy. Since APC no longer produces the Back-UPS Pro models, and the regular Back-UPS models don't have easy battery replacement or a display, I chose this Eaton Ellipse Pro 1600VA, which I found at an excellent price. It's my first time using Eaton, but I've heard good things about it. After a few days of use, I can say that it's a good UPS, even heavy without batteries (although its casing is plastic and not metal like the Legrand), with multiple output sockets and good features. Its display provides a lot of information and basic settings for input power, output power, ECO mode, and Alarm ON/OFF. The ECO mode allows 4 out of the 8 ports to completely shut off power when they detect that only the power supply of a connected device is on, which is supposed to save energy. The batteries (2x 12V-9Ah) are easy to replace. The only "issues" I found are that its output is not sinusoidal (like more expensive online UPS), but that doesn't cause any problems for computers, and that its fan runs continuously (at low speed), resulting in a low continuous noise. The latter makes it unsuitable for a bedroom, but under normal household/office conditions, it's not a problem. I didn't install its software (USB connection), so I can't say anything about it. Also, it doesn't have/take an Ethernet port for remote monitoring, not even as an option, but no UPS in this price range has that. Another thing I liked is that Eaton provides nice installation and battery replacement videos for their UPS. Overall, this UPS is very good for its price, and to get something better, one would have to maybe spend twice as much.
[update] As one would understand from the continuously running fan, the UPS doesn't have a separate power supply for battery charging, like most stand-by UPS do nowadays. The result is that even with zero load, it consumes around 35W.