I've been using a AV200 HomePlug adapter for the purpose of connecting my ethernet only media devices to my router upstairs. It does the job but the throughput isnt amazing with the old wiring in my house.
After trying the AirTies 4420UK-TV it does a very good job at passing multiple streams around my house. I have my PS3 streaming 1080P video from my NAS and my Media Center streaming live TV upstairs to my Xbox 360, and it coped very well. This is also a good way of increasing the speed of the PS3 "wireless" connection as the built in one is only 54mbps.
Where this device is really useful is its pretty much plug-and-play nature, you just plug it into the devices you want to link push the AirTouch buttons and away you go! The same goes for the built in media server (which works with my DNLA enabled TV and consoles), plug in a memory stick with a video files and it gets streamed to whatever you have the other adapter plugged into. Unfortunately i could only get it to work with a FAT32 formatted drive, it just wouldnt see my NTFS drive so videos over 4GB are a no-no.
There are advanced settings to control some of the more complicated aspects of the adapters using the supplied software disc. Advanced wireless security, Muti SSID's, Dual band wireless access point, Wireless video streaming and MESH networks and a built in firmware update to ensure they are always up to date!
One small gripe is the mislabeling of the connection speed. While the wireless link may indeed be 300Mbps, the wired link to the router or device is only 100Mbps, which is fine for most cases but coud have been beefed up to 1Gbps so there isnt any bottleneck.
All in all a great device if you dont want to run ethernet cables around your home and dont already have wireless N connected equipment.
4/5 because of the low speed ethernet port.