I've been an X10 user (8-12) channels, a
timer, and various transmitters located all
over this under lit 100+ year farmhouse and
barn, for many decades - starting back when
the equipment was chocolate brown and labled BSR.
I've used just about every home automation
product they sell, and sold, and will mention
the best and worst parts when it comes to
reliability:
Unfortunately the wall switch is one of the
worst - it fails in one mode or another, or
altogether. Transient sensitivity? Maybe
and sometimes. Use a Socket Rocket if
possible. Before the "Rocket" existed, I
used to dissasemble lamp modules, remove
their plug and socket parts, and hard wire
them into the fixtures. They are very
reliable too, as are the plug-in appliance
modules.
One of the best is the wireless motion
sensor. It has incredible battery life,
works in a wide range of temperatures, and
works the vast majority of the time, even on
nearly dead batteries. When it doesn't work,
it's usually a signalling collision.
Excellent design. No failures. (They have
an ambient light sensing mode, but I couldn't
seem to make it work, but it's really not
needed in most situations. Just the auto off
saves electricity, even if it does operate in
the daylight.)