Remember that UPS's have three drawbacks:
-They're heavy and expensive
-They contain a switchmode power inverter that can (and often does) generate RF noise that can be heard in amateur receiving equipment
-And most of them, unless very large, very heavy and extraordinarily expensive, won't power your amateur gear and 40A power supply very long at all!
The typical UPS that you can lift and carry around will provide 300W for 10 to 30 minutes, if you're lucky. The ones that will provide more than this (more power, or longer time period) get big. An "emergency" such as fire, flood, earthquake, hurricane, tornado...or even a trainwreck, etc that happens to take out the local power lines...can last several hours to several days (or even weeks) to clear up, before utility power is restored. A UPS that provides "emergency" power for 30 minutes isn't going to help when minute #31 rolls around.
UPSs are great for isolating your equipment from temporary spikes, surges and brownouts -- and that's what they're for. For true "emergency power" for radio equipment, I'd go for something else.
WB2WIK/6