The TP Link looks interesting and simple.
I'm assuming one unit plugs into a wall socket and then into your router via ethernet cable and then any additional units just plug into the AC.
The only issue I would have is that my house is old and has two sets of AC lines, the original lines plus additional new lines. I know which are which and would just have to make sure all of the TP units are plugged into the modern three prong outlets which are all on separate circuits from the original wiring which is all two prong.