When I got my EERO router when I switched internet plan, the signal was not very good. It was slow and I had problems staying connected. This is because when I first had internet (and cable) installed in my house (a long time ago), they decided to install the connections on one side of the house. I tend to be on the other side of the house most of the time.
I couldn't take it anymore and so broke down and spent the $80 for this extender. It was easy to setup and my connection is really good now. It definitely works!