I moved form X10 due to lessening reliability, I suspect caused by the increasing number of other electrical devices plugged into my house. I had gone to the trouble of whole house filter, individual device filters, high power X10 transmitter but nothing helped.
I still have a couple of X10 controlled lights (shortly to be replaced)and they sporadically turn on by themselves.
Initially, I moved to Insteon for the X10 compatibility but the lack of devices for the UK and poor build quality has sent me down the Z-wave route.
I like the idea of on-borad eternet for Comfort.