They've been very useful in situations where wifi didn't go far enough. I find them to be more reliable and faster than wifi mesh networks, up to a few hundred megabits.

They do come in different speed ratings though, and those still depend on the condition of your house wiring.

Buy them from somewhere with a good return policy and give em a shot.

Moca is another option if you have coax wiring for cable TV in your house. That's nice cuz it doesn't share bandwidth with power lines.