I have a couple of these running across my house, I went for the Solwise AV (200mbs) units which not only look nice, they are pretty quick too. Solwise sell 'pass through' versions too, with a socket on the back, so you don't loose important power sockets. They also have one with about 3-4 sockets on I think, which looks like an extension cable and finally one that is built into a router.
I run them from a Virgin line > Modem > Wlan Router then through Solwise AV into a second unit, then into Gigabit switch to my PS3, Netgear NAS and upstairs PC.
I've not tested performance yet, but with encryption on I was copying files waaay faster than I ever could over wlan.
I paid about £45 each for these units, so not 'that' cheap, but the reviews were very good on the net.
They get my vote
Rich