It seems there's a UPS Guide
on this forum so you may also check that out if what I explained doesn't make sense or if I may be wrong on some points.
Purchasing a UPS isn't just about buying the reputable brand but what you actually need to use it for. You have to ask yourself a couple questions and do a bit more research. It's probably best to measure how much power you actually pull from the wall outlet to power your system from idle and maximum load.
Is your computer around dangers of weather (lightning/storms) or high powered electronics (high-wattage power tools)?
Are you looking to just properly shut down your computer during a black/brown out (sudden loss of electricity)?
Did you want to have some headroom to keep your computer running when the electricity is out?
You may be purchasing a 1200watt power supply but that doesn't necessarily mean your system is capable of pulling that much from the wall so it's personally up to you if you want a UPS capable of that much or more for headroom in keeping a system on longer for emergency needs. That's where a wattage meter is put to use so you can measure your actual usage. Another thing to keep in mind is that after a UPS capacity limit, you will need to use a different plug to go higher (usually around 1000+ wattage in the USA to use a higher rated socket). This starts going toward the point of contacting an electrician if you want to change the wall socket or if your household/room is capable of supplying that power.
My recommendations is that a UPS is great to use by supplying clean power to your system or any electronics that will be using it. However, it's really not worth it if you're just trying to protect your system by typical spikes in a household unless the household itself is bad in supplying power to the point that turning anything on would cause the lights to dim for a couple seconds. Personally, I think it's best to get a UPS when you have bad weather conditions (generally lightning storms), constant use of high-powered machines/tools, keeping a server off of downtime from a quick electrical outage, or constant quick outages based on your experience with living in your current location.
If you still feel the need to get a UPS based on your needs then please do so. The only brands I've looked into are CyberPower and APC. I've found CyberPower to be more user-friendly. Otherwise you're better off just saving money by getting a decent surge protector. Keep in mind that this is all based on my own research and opinion as I'm not a PSU/UPS expert.