How good is ethernet over electrical sockets these days. I had one about 15 years ago maybe, but it wasn't that good.

Has tech changed. I'd use it over my wifi setup if its was fast.

This tech is known as BPL(broadband over powerline) if you want to look further into it.

I used the regular home power stuff many years ago and the speeds were pretty bad and the network loss was unreliable.

My understanding is that it has improved in some circumstances, but if the connection ends up "hopping" through your breaker you get back to garbage speeds.

In theory you can get 2 Gbps speeds, but in practice it seems like still around 500 Mbps. I don't know if the loss has improved but it was a significant problem before, since even a low loss will render a connection unusable.