Was having trouble with Wi-Fi drop-out on my PlayStation 3, it being the device furthest away from my Wi-Fi router, making stable connection frustating and game downloads incredibly long-winded.
I bought these Ethernet Powerline adapters and was instantly impressed with what they do.
Almost zero set-up is required; plug it in at router, plug it in at device, press little "sync" button on the plugs, done. Took 2 minutes.
PS3 is now faster than ever with connection speed and downloads. Can't recommend them enough over Wi-Fi.
NOTE: The kit comes with two Ethernet cables for you to use but some people may find them a little short depending on their setup, luckily I had a few longer ones from an old router that I used.