In my knowledge and also hands-on experience with a set of PE adapters, there are zero to very few PE adapters that can actually achieve the speed as advertised on the box.
I once owned a pair of 500 Mbps PE adapters (from the "Buffalo" brand so not cheap Chinese ones) and when plugged in the same mains power strip they could not reach more than about 200 MBps.
When plugged in wall sockets in my house which are on the same group (so using the same fuse in the fusebox) I could reach "usable" speeds for web browsing etc.
When plugged in wall sockets in my house which are not on the same group speeds were often terrible.
In the end I sold the PE adapters and installed proper ethernet cables instead.
So my advice: if you can live with not-so-great speeds then get the cheapest 100 or 200 MBps PE adapters you can find. Maybe even buy used ones. If you care about having high bandwidth: forget about PE adapters, install proper cables.
Mains Power cables aren't designed for high speed data transfer and even the fanciest PE adapter cannot fix that. For a short distance (couple of meters) with sockets on the same group it can be good enough. Anything else is a no-go if you ask me.
Why not just use WiFi? – Phil N DeBlanc – 2018-04-09T19:29:26.040
@PhilNDeBlanc I tried pure wifi but had issues with signal degradation/deadzones. I installed a wifi extender and it addressed some of those issues, but still isn't as reliable as wired internet. I've noticed it most signficantly when remoting in for work or gaming online. – lintmouse – 2018-04-09T19:34:26.683
@lintmouse Ah, ok. Well that blows. – Phil N DeBlanc – 2018-04-09T19:41:25.767
1Do the hard work and run a real CAT5 cable from the one room to the other. It's not a fun project, but after you're done, you'll be glad you did it. :) – Charles Burge – 2018-04-09T23:26:16.873