We recently moved into a new house with WiFi eating walls. After some research I ordered a TP-Link AV2000 Powerline Network kit and we have been very pleased with the results. I have a more detailed review in the Network section, but here's a summary.
Performance is great. Nowhere near the marketing/advertised speeds, and not as fast as direct wired Cat5E/Cat6 Ethernet, but still impressive. We are on 100/100 megabit FiOS internet, and we get full performance all the way to the furthest corner of the house. Our slowest powerline node is operating at over 600Mbps, which is far from the 2Gbps advertised speed, but still many times faster than our ISP speed.
This is how our powerline network performs.
The big advantage is that you can install this yourself in just a few minutes, and if you rearrange things in your house later, it's simple to move your network ports. We were so happy with the performance we got from our first kit we ordered a second kit which included a dual band wireless AC1200 access point to improve WiFi coverage downstairs. Note that a powerline access point is more secure than a WiFi range extender, and it can be located anywhere you have an outlet, even where there is no WiFi reception.
See my review for more information.
My password is the last 8 digits of Pi.