Summary: Pros: Very convenient and more reliable than wifi. Also supports easily adding additional AV 200 nodes (I have 3 that talk to each other, to bridge wifi-enabled APs/routers/switches in the family room, office and upstairs guest room). Cons: Powerline networking devices seem to get only 20% of the advertised speed.
Summary: I already own the Netgear 85Mbps Powerline Network Adapter XETB1001, which I use to stream HD 1080 from my server, it has worked flawlessly for 2+ years, a single HD stream requires ~6.6Mbps bandwidth to work well. I decided to upgrade to a newer version of HomePlug, so purchased the ZyXEL PLA401v4 HomePlug AV 200 Mbps Powerline Wall-plug Adapter kit. I unplugged the Netgear units, and then plugged in the ZyXEL in the same outlets, no encryption.
Summary: I bought this device to work together with a couple of linksys pl 200 power line devices. The device would not recognize the other adapters at first, I had to use the cd and plug the device to a pc in order to recognize the homeplug compatible devices. If you read the skimpy manual, it says so in the last lines of configuration. I guess its plug and play compatible with other zyxel devices, I might purchase another to test it.
Summary: Initially I bought a pack of 2 of these, as I have previously used Zyxel HomePlug units (the earlier 85 Mbps units). For those who worry about these things, these units do not have mains pass through, so you do need to have enough sockets in appropriate places to work with. There are two ways of configuring them (1) with Encryption, and (2) using a management utility - on the supplied CD, or which can be downloaded.