Spyware:

 

Until you turn the washing machine on.

 

In the few cases I have used powerline I've never noticed any stability issues and that was with old units. I'm sure they have improved a lot since then. I used a set to get to a farm shed about 500M from the main house that worked for years until eventually being replaced with high power mesh wireless. It only got about 20meg but that was better than nothing.