The basic design of Netcomm's Homeplugs hasn't changed markedly over time. Buying a double pack of them — and outside of the wireless NP290W, it's always made more sense to initially purchase double packs — always entailed ending up with two big chunky plugs with 10/100 ethernet ports more or less drilled into the bottom of them. There has been some evolution of the design — the NP200AV plugs have a whole lot more ridges on the sides and front, although we're not sure if they're intended for cooling or just aesthetics. Given that they don't actually open the plug up in any way, our bet is on aesthetics. The other major difference between the NP200AV and its ancestors is that the plugs themselves aren't entirely black; they're a two-tone purple and black instead.
The big selling point of the NP200AV is the ability to deliver networking through home or office powerlines, simply by plugging one end near a router (or other network source) and the other end wherever you need your network port. In the NP200AV's case, the claimed speed is the real selling point; Netcomm claims data rates of up to 200Mbps for the 200AVs, making them suitable at last for real-time high definition video streaming.
There is one caveat to note for existing Homeplug users. Whereas the previous Netcomm Homeplugs offered backwards compatibility between the faster 85Mbps models and the pokier original 14Mbps plugs, the NP200AV's aren't cross-compatible at all. It is possible to run a 200MBps and split 85/14Mbps Homeplug networks in parallel, however.