My experience has been different. Wifi extenders were not very reliable. Wifi devices were better, but powerline extenders have been rock solid. Ping times are right in line with wired Ethernet too.
In my experience powerline extenders are a reasonable alternative to Ethernet for home users in places where running a cable isn't an option.
I have them installed in 2 houses, one 120V and one 127V. Electrical panels in NA are pretty simple (although not as simple as the UK) and have the 2 phases split on the 2 sides of the box. The breakers for 120V or 127V circuits on the right are on one phase and those on the left are on the other.
The panel wiring wasn't something I thought about when I put the power line adapters in and they were plug and play in both locations. I'm guessing some brands work much better than others and these Netgear adapters have worked flawlessly. Or maybe I got lucky.
That said, I'd have Cat6 cables installed if it didn't require tearing apart the walls and ceiling.