My home plugs are not very good, although it could possibly be due to the wiring of the house or interference but the speed isn't very good and they occasional disconnect from the network then reconnect. I get a better speed and a more stable connection through wireless surprisingly. I wouldn't want to add another home plug at the router end because the ones I have cant take much through put, these are generic 85MB ones from the rain forest place. I wouldn't want to have loads of them because there is only one plug at the router end having to accept all of the data, if you are just having one of them then it would be OK. But having any more I would say get a decent router with good wireless and get a good wireless adapter for your PC.
Although this is just from my experience.