I am considering a networking kit that uses my home's electrical wiring to create a speedy and reliable network. What brands are dependable and what are the gotchas and caveats to keep in mind?

It depends on quite a bit, but mostly your wiring. Noisy electrical power isn't usually a problem, as these things are designed to deal with that... they're operating at frequencies orders of magnitude higher than any noise you're going to see in a 60Hz power system. It's just filtering, the same thing needed with WiFi -- if you think powerlines are dirty, look at the "air" sometime (I used to design RF systems in Philadelphia... any city is a jungle of evil radio signals all fighting with each other). As with most networking, the rated speed is a best-case rating. These behave a bit more like RF systems than you might expect given the wiring, in that distance will have an effect on performance. The common "500Mb/s" network is based on a technology called HomePlug AV, which uses up to 1155 OFDM carriers -- 802.11 and most cellular networks also use OFDM modulation. The HomePlug technologies fall under the auspices of the IEEE 1901 standard which, like the most well known IEEE 801.11 standard, includes a large number of different technologies under one umbrella standard. I have a HomePlug AV network set up in my house. I have Gigabit Ethernet connecting my computer room and and my media room, and 802.11n wireless in the house. I also have a DirecTV video server in the house, with two client nodes connected to it over DirecTV's coaxial "DECA" network, which is bridged as just another segment of my GigE network though a switch and the video server in my media room. Simple, eh? When I went to add a client node upstairs, I didn't have any simple way to run any kind of wired network.. I have kind of a weird house with two main A-Frame sections and no attic for easy wire drops. So I originally put in a second 802.11n AP in my media room, an 802.11n AP configured as a client up in the kids' TV room, and attached the DirecTV box via a 100-Base-T to Coaxial networking adapter. All of this of course, is completely outside of anything the DirecTV folks will recommend -- if you're lucky enough to find anyone at DirecTV who understands how their media networking works, even slightly, you ought to be playing PowerBall this week... but I digress. 802.11 isn't the best thing for media streaming. This worked... but it was flakey. And the network could get disrupted just by someone walking through the room. You'd never notice this using 802.11 to get to the internet, but this is all designed to be very realtime dependent, with only a second or two of buffering. They expect a reliable network. I put Home Plug AV devices in as an alternative, and it works dramatically better. I haven't bothered to run iperf or anything and actually test the performance, but it's reliable enough for glitch-free DirecTV HD streaming (probably less than 10Mb/s AVC in an MPEG-2 transport stream) and any web surfing you can manage ... I'm only on Excede Satellite for ISP, that's a peak of about 12Mb/s down. Works good, and fast. That is a fairly recent development. Early versions of power line networking were slow and unreliable. Today's CAN be fast and reliable. No guarantees, and you're probably not about to rewire your power lines if you don't get a good result. Just be sure to buy the units (I have a Trendnet pair) from a vendor with a good return policy.

I've been using some 500Mbps TP-Link modules for the last 18 months (7 connected atm) and prior to that I used a pair of D-Link modules (200Mbps). I've not heard of any issues with the main brands, so I think generally they're all as good as each other. Although there are now open standards for power-line networking, and some support for backwards compatibility (so newer-purchased, faster, modules will talk with older ones), I would recommend trying to keep all the modules within the same brand. Some extra features (including transmission encryption) plus 500Mbps+ don't always talk well between brands. However, the biggest cravat to be aware of is the wiring in the house itself. I live in an old house, and some of the wiring isn't great. Although I use 500Mbps modules exclusively, peak bandwidth never really reaches above around 70Mbps. Plus this is not a switched network - that 70Mbps is shared among all points on the electrical network as they all share a single cable effectively. If you're moving a lot of data round (say, copying files from your PC to your network drive), that can have knock-on issues with other connections, including the Internet (depending on how you configure the network). In general use, I've configured my network to make best use of these limitations, as the only way to upgrade is to route dedicated UTP cables around the house. Nonetheless, keep in mind that this is essentially a hack of a solution to prevent the need to do this and often provide faster speeds than wireless while taking the load off of that network at the same time. Keep an open mind, stick to a common brand, be aware of the limitations of the technology (and work around it where possible), and you should be fine.