It would be interesting to know; of all the 4301 members that are register to this forum; how many have solid, error free working systems. I don't ... and I think I have a pretty simple setup!!!
X10 can be virtually 100% reliable, but it takes some work. We have used X10 for almost 30 years - since the brown BSR modules first came out. Over the years we have certainly had failures, and fought problems. When we built this house I planned an X10 installation from the start. We use it for all automation: irrigation, ventilation, hot water circulation, and of course, lighting. It is not a simple system.
Planning ahead, we had a special circuit run for known problem loads - computers, A/V equipment, and other electronics. That circuit is fed through one of the big XPF filters to keep those loads isolated from X10. Then I installed the small Leviton 6287 noise blocks in every lighting circuit that would have compact fluorescent bulbs. Finally, I arranged our electrical panel so every circuit that could possibly need X10 access was on the same phase.
After that, we had almost 100% reliability from our Ocleot via a PSC05 located about 30 feet from the distribution panel. One living room lamp with a CF bulb would ignore its OFF commad every few months, but everything else worked fine.
I did notice that our central circuit with several transmitters and a bunch of X10 lighting circuits had a relatively low signal level. A Leviton 6201 repeater didn't help much, so I developed the XTB to drive some real signal onto the line. Just plugging the PSC05 into the XTB increased the level on that low circuit about 300%. With the PSC05 / XTB located near our distribution panel, that circuit came up from .1V to 1.0V, as measured by the ESM1. Even that cranky living room light has behaved since I installed the prototype XTB.
The bottom line is that yes, there are those of us who are completely satisfied with automation via X10. It offers a lot of bang for the buck for those of you willing to put the effort into it. A signal measurement tool such as the ESM1 is perhaps the most valuable factor in creating a reliable system.
