If I were to start over, I'd use UPB. I just don't trust smarthome to get it right anymore. I'm even more afraid of how they could manage to mess up insteon.
I mean, if they can't even get a simple thing like congestion backoff working, then what hope do they have on something complex?
Pop quiz: what happens if you query three smarthome switchlinc-relay devices for status together?
Answer: you get to make a trip to the breaker box to power cycle them. because they're generating massive amounts of 120KHz noise and totally trashing any hope you have of using X10 again.
I had two switchlinc-relay devices next to each other for the kitchen lights. My wife has the knack of pressing the toggles in such a way that they're close enough to simultanious as to cause them to get into the retransmit loop and take out the X10 network. Using a grouped status_request is dead simple to trigger it - it takes more skill to trigger it from the toggle buttons. Grouped X10 status requests are silly commands to send, but they demonstrate the problem spectacularly and easily. The bug is far more pervasive than that though - I can reproduce it by simply power cycling the breaker (about 1 in 8 times on our house), or as often as once every 1-2 days when my wife is home.
Also, the 130KHz-ish insteon carrier is awfully close to the 120KHz X10 carrier and we all know how many things absorb the 120KHz signal. If Insteon uses an x10-style tuned circuit to transmit the carrier, then they'll have the same problem with multiple transmitters absorbing each other's signal. I sure hope they get the every-device-is-a-repeater algorithms sorted out and working!
I've checked and can reliably control my test UPB appliance modules when plugged into a neighbor's house, 6 doors away, other side of the street. I can't even reach half of the 120KHz devices in my own house reliably. I did resort to a passive phase coupler to improve the upb signal in the other phase. It was amusing that I got better UPB connectivity to the other phase at the neighbor's house than to the other phase in my own house. Anyway, I get "excellent" signal (100% signal strength, 0 noise) everywhere I've tested in my house on the same phase, even through a GFCI. I get "good" signal (40% signal strength, 0 noise) on the other phase. No dead spots, even when the modules are plugged into surge arresters etc.
That being said, I'm going to tinker with insteon out of curiosity (I have a devkit). But I'm going to keep on gradually replace my troublesome smarthome switchlinc-relay devices with UPB devices as they annoy me. Fortunately, I've got rid of the two worst offenders (the kitchen). The reason I'm curious about insteon is because of the supposedly dramatically higher data rate. But I'm not sure if I'm willing to trade data rate for firmware bugs or unreliability especially when UPB has so far had a perfect reliability record for me. (every single command acked on first transmission attempt so far, according to the logs)
In case you didn't pick it up, I'm still peeved at smarthome for not having a clue how to reproduce this or what to do about it.. that's really great after spending something like $5000 (or more) on their stuff. I seem to get the blow-off response because the easiest way to provoke it is a useless (but valid) X10 command. I sorely regret buying things from them now. That reminds me, I have got to RMA some dead switchlinc-relay switches.
Z-wave is out for me, I already have too much 2.4GHz noise in the house and nearby. I don't need the aquarium controls to go offline because the microwave is turned on or something silly like that.
-Peter