I have the Netgear Powerline HD boxes too.

I have tried using them in three different houses all with the same result, totally unsuitable for streaming SD or HD video.

They start off well, but when you start plugging in computers around the house to use the Powerline network the signal degrades depressingly quickly to a point where it reports that it will take 14 hours to move a 700MB movie file over it.

Oh BTW the solution to improving the bandwidth on the Netgear boxes is to 'Reduce the noise on the line' but no advice on how you do that.

I guess I am back to running a cable too.