Been using X-10 in my past three houses for over 20 years. My first X-10 products were BSR, really goes back a bit.
Have had good and bad experiences with X-10. With the right whole house filter and careful use of module filters I was able to get it to function. But, (big but here) any new device on the house power grid could set off X-10 issues caused by noise and signal attenuation. In building the last home 12 years ago I again used X-10 mainly because I could not afford better controls.
Now, 12 years later I am finally replacing this X-10 system. I have decided to replace it with a UPB based system. I am still disappointed that the cost has not decreased more. I have to replace over 50 controlled locations so the cost will be high for my budget. (and I am cheap, frugal, etc!).
So, I have purchase mostly Simply Automated devices. I like Web Automation products but they are often more expensive. PCS and HAI are way more expensive but I think better quality products. I have had a HAI Omni Pro since 1990 and have recently replaced it with a HAI Omni Pro II system. Both have been first class products and have worked well with X-10 control. I have had no issues to date with the control of UPB products and don't expect any. I am about half way though the replacement process. The delay is just trying to spread out the cost a bit.
X-10 hang overs.
Remote controls seem to be few and far between for UPB so I am using the various X-10 remotes I have. I am able to control the UPB units by using the UPB572 by wgldesigns.com.. Seems to work well so far and it has good range.
I still have 11 X-10 sensing spotlights that I would like to replace with UPB units but none seem to exist. I have seen DYI solutions and may be forced to take that route. I wired this new home myself and in doing so installed switches for each outside spot. So I can give up the sensing and just use a UPB controled switch. But, really like the sensing so that will be my last resort.
Overall, UPB as been a joy to work with. No issues to speak of, just a lot more programming to deal with. But that is the fun part.