I bought a couple of these to avoid having to run network cables through my house. The house is ten years old, so the wiring should be decent and it appears that it is. I plugged one unit into the mains downstairs, where I connected it to my router. I plugged the other unit into an eight way adapter in an upstairs room, although they recommend plugging them directly into wall sockets. I connected this unit to my desktop PC. Then I pressed the synchronisation button on each unit, they connected and that was all I needed to do.
They work just like having a cable straight from the router to the PC. The only software is a utility you can use to upgrade the firmware on the units, but there was no need to actually do this.
The only negatives of this solution are that they use power all the time, have multiple flashing lights on them and I can hear them. They emit a very high pitched whine, like a charging camera flash. My wife can't hear it at all, so I guess it depends on how good the range of your hearing is.
All these problems are easily solved by turning them off when not in use. When you turn the power back on they seem happy to reconnect and work without any other input.
Overall, I'm very pleased with them.