I think we've gotten a little off-topic from the original question about other home-automation systems as alternatives to X10. Everyone will have a different experience, even with the same technologies. I have a neighbor up the block (different pole transformer, though) who had horrible luck with his X10 system, and decided to switch over to Insteon a few years ago. He had a difficult time getting it set up initially, because he needed to find the right combination of outlets for the wireless bridge modules to be effective as a phase-coupling pair. Once he got that straightened out, however, he has had a very reliable system. He isn't all that thrilled with the Insteon software, but the signals work just fine.
I also have had a number of problems with my X10 system over the 8 years since we moved into this house, but I decided to stick with it and make an effort to fix it (a number of well-placed filters, and Jeff Volp's XTB-IIR, were a huge help in my case).
My point is, every installation is different, so there is no one correct answer for everyone.
The right system for anyone is the system that works best for them.