Hi,
I'm not sure what metal boxes have to do with anything other than, heat dissipation?
I am a X-Insteon, happy Z-Wave user. The sad thing I have to say is that I am not aware of any Z-Wave devices that can approximate a Insteon KeyPadLinc in functionality. Z-Wave devices are also more expensive.
Insteon is MUCH better than X10 for noise immunity. Insteon's improvement in that field was to make each device a powerline repeater. They call it a 'Mesh Network', I call it a bunch of dumb repeaters. The reliability part came in with error checking. If a signal can not get through, at least Insteon will let you know it failed.
IF you indeed had problems with a X10 switch and a X10 PLC transmitter, then Insteon will not improve things. If you had a lot of X10 switches and one transmitter then Insteon can help (each switch will repeat the signal and make it stronger).
Z-Wave is still very new. The really cool software is still not available. Z-Wave advertises their devices at generally 50 feet line of sight. I read an article today on the Insteon RF linking devices, they claim 150 feet. Since Insteon has no true RF remote control devices, that would be hard to dispute. I would tend to believe the Z-Wave claims as they operate on similar frequencies at similar power and have actual operating devices..
Contrary to Insteon claims, Z-Wave modules are not cryptic unprogrammable devices. I have had much more trouble with Insteon broken links than anything they can say about a broken Z-Wave network device. I had more trouble understanding Insteon linking instructions than Z-Wave (and that aint saying much for either). My Z-Wave devices serve the purpose that I purchaced them for very well. I have hundreds of dollars worth of Insteon devices that are in various stages of being junk, depending upon some magic firmware fix. Given Insteon is fixing all of this, if I were to recommend a good OPERATIONAL control system to anyone, well...
Pardon the advertisement but I paid for it with a lot of electrician work and many hours spent on work developing Insteon software.
In my humble opinion, PLC devices will never work in noisy PLC environments. The RF stuff works fairly well. The only people that I have heard bashing it so far are the one deep in debt to PLC.
(you all should probably start a different thread to flame me on)
Ken