1400VA and 700W is the figure that makes this the unit that matters — it is the only one of the two with headroom for a desktop, a monitor and peripherals at the same time, and the reason the load is split across two boxes rather than one. Six battery-backed IEC outlets mean a full shutdown is a single clean action rather than a scramble. As a Back-UPS rather than an Easy UPS it sits in APC's better-supported line, though the feature set here is still deliberately basic.
It carries the desktop, so an outage gives long enough to save work and shut down properly instead of watching the lights go out. It is the unit that has to be sized right, and it is.
This part is discontinued, so a replacement has to be second-hand and the battery — which is the component that actually fails — may be well past its life regardless of the unit's condition. There is no USB port on this model, so PowerChute cannot coordinate a safe shutdown and that has to be handled manually. Like the smaller unit, the output is a stepped sinewave.