In the cold weather, it was open all day and kept a large room with poor insulation at satisfactory temperature levels.

Negatives:
It does not save the weekly schedule if it loses power, so the whole function becomes useless.
Positives:
The most high-quality construction I have seen in this category. They say that a device is judged by its cable. This one does not have a simple PVC cable but a fire-resistant silicone one.
Since it was installed in a bedroom, I opened it to check it internally. High-quality silicone wires, and the thermostat cable has a fiberglass insulation. The heating element is not one of those simple "bare" resistors that pose a fire risk if dust accumulates, or if a child puts something conductive, there would be a risk of electric shock. On the contrary, it has a PTC (ceramic) type resistor, which due to its increased surface area poses no fire risk in case of dust, and it is not electrified (the surface).
Also positive, the air vent is on the sides and not on top, resulting in no dust accumulation inside for safety reasons.
If you have space, it would be better to get the 1800-watt version; regarding power consumption, they will consume the same since the 1800-watt will reach the desired temperature faster and the thermostat will turn off quicker.
Finally, for those who refer to the heating capacity of air heaters - convectors, etc.: All have the same efficiency, which is almost 100% conversion of consumed energy into heat, unless you find a product that moves around the house, in which case a percentage will be converted into kinetic energy. To achieve higher efficiency, you need to switch to a heat exchange method, that is, a heat pump - air conditioning that provides over 200% efficiency.