Most of use use wireless to connect the devices in our home, but as we've discussed before, wired is usually faster, even if it's through your wall with a powerline adaptor. With wireless AC, however, the game has changed a bit.
A direct wired Ethernet connection will always give you the best speed, but if that isn't an option, powerline and wireless are your next best bet. NCIX compared powerline with wireless AC in the video above, and found that wireless AC actually performed better — as long as the distance was short. Powerline was more consistent, and performs better over long distances, where wireless performance starts to degrade.
Your mileage will always vary, depending on your house's wiring and your walls, but it's good to know how far wireless has come. Check out the video to see the test in action, with a bit more explanation on when it's better to use one over the other.
Wireless 802.11 AC vs Powerline Real World Test [NCIX Tech Tips (YouTube)]