There's no doubt that Ethernet-over-powerline adaptors are a brilliant invention. As convenient as Wi-Fi is, there are times when it simply can't provide the constant bandwidth wanted for streaming high resolution video, or transferring large files without going mad with frustration thanks to the process taking so long. Even 802.11n doesn't solve the problems of Wi-Fi entirely. For one, a lot of devices, such as many TVs and both the PS3 and Xbox 360, don't yet support the standard and for some purposes, primarily online gaming, the latency of a wireless connection is most undesirable.
Traditionally powerline Ethernet adaptors also offered similar cable-reduction benefits to wireless, too, eliminating the need to trail Ethernet cables around your house to get a decent, stable, high bandwidth connection. With an every growing number of devices needing an Internet connection, however, the cable clutter is returning. It's not hard to imagine having a TV, a Freesat box a PlayStation 3 and/or an Xbox 360 and a Blu-ray player in your living room all wanting access to your router.
It is, of course, entirely possible to use an Ethernet switch to connect all of those systems to a single powerline adaptor, but that's a rather inelegant solution, not to mention one that sacrifices a power socket which is hardly convenient when a lot of adaptors still inexplicably take up two slots by themselves. The alternative solution is to combine that Ethernet hub with a powerline adaptor, which is exactly what the Netgear Home Theater Internet Connection Kit does.
The kit combines a four-port Ethernet switch with an XB101 adaptor, as found in the HDXB101 package. The packaging claims a maximum transfer speed of 200Mbps, which is a little misleading. That figure is a theoretical maximum (with the Ethernet connection running in Full Duplex mode which is fair enough), but unless you're using two adjacent sockets or have implausibly high quality copper wiring in your property you'll never see anything like that transfer speed.
Given its pricing, this kit competes quite closely with the Solwise Piggy6 HomePlug adaptor. Bearing in mind you have to add an adaptor costing about £40 to the Piggy6 to get the same functionality as the NetGear system, both cost just shy of £110 all in. While the Piggy6 has the convenience of combining its HomePlug functionality with a surge-protected power strip, the Netgear kit offers an extra Ethernet port. Which is more useful is debateable, but for me the extra port is the clear winner as I happen to have four devices needing a 'net connection in my AV set-up.