Each preceding level contains elements of the previous one. A Power Conditioner is basically a surge protector with a big capacitor or a small battery. A UPS is a battery, and your computer runs off a complex circuit that feeds power from and to the battery. Very expensive, usually build in systems, may contain fly wheels, generators, or other power storing/generating devices. Most consumer level models use batteries, and they will need replacing from time to time.
APC is a good company. I like them. We have well over a dozen different APCs and we love them. Apple lists the
Pro500 Clear . I use an older version of this on my work computer. Our grid is poor, and our building is poorly wired. The APCs get a good work out, and havn't faild yet.
You dont need to have connectivity to the UPS for it to work. When the power fails, is not clean, or is below tolerance, it kick in. They should work seamlessly. If your running a server and it is unattended, or the system you are using is processing wile your gone, then it would be prudent to get an UPS with compatible software. In this latter case, make sure that the UPS connects via USB cable to your computer (for data).
If the power in your area is very unstable, or large power spikes are common, get the best unit you can afford (the one with the longest up time). A good UPS will also warrant their device and insure you against damage to your systems. Limitation apply, and they give you hoops to jump though, so read the fine print.
I wouldnt concern myself with the automatic shutdown and power monitoring software. A good UPS will have these functions, but its general operation will be automatic. Beyond you attaching the battery, its first full and unloaded charge, and you plugging in your equipment, it should be require no user intervention.