And now for something on topic. I have X10 (smarthome products mostly), UPB and Insteon in my home.
My personal likes/dislikes:
X10:
+ Ubiquitous
+ Every device imaginable exists
- LOUSY reliability (even with repeaters etc)
+ If you can tear your house apart, a Lightolier compose firewall might be the ticket. (But I would not be suprised in the least if it turns out that it will out Insteon 131KHz carrier signals as well....)
- System degrades as 2-way devices are added. (Each transmitter sucks more signal away)
- Carrier signal seems to be readily absorbed by many devices in the house these days.
- The high efficiency ballasts for my aquarium tank lights cycle at 60,000Hz. They seem to totally destroy X10 signals nearby (X10 running at 120KHz).
UPB:
+ Exceptional reliability. Absolutely supurb! I'm even using them on the wrong side of a GFCI on the wrong phase, outdoors on a 50-ft extension cord in a waterproof box with 100% reliability. I have something like 10 appliance modules, most controlling fish tank lights and water management. I actually trust it.
+ Carrier signal seems to be quite immune to signal absorbtion so far.
- Carrier signal didn't jump to other phase with any real reliability, as the promo material suggested it should. A cheap passive signal coupler solved that trivially though.
+ Excellent signal propagation. We get "excellent" signal from my computer controller to our neighbor's house. A priceless April fools day prank resulted this year.
+ Computer programming interface is nice. I wrote my own software with no hassle.
- Light switches suck! The body is larger than even the old smarthome devices and won't fit in this house's J boxes. I have to replace the J-boxes to make them fit. The bodies are too tall.
- Light switches double suck! The rockers try and detect single vs double tap. They do this by waiting for something like 1/4 to 1/3 of a second. This is really annoying when both cases are programmed to do the same thing (turn load on instantly). This adds significant user-visible delay to button presses. I dearly wish there was a way to disable the double-tap detection delay. But there isn't. Aargh!
- Expensive! (Well, compared to X10 and smarthome stuff. Not so expensive compared to Z-wave it seems)
- Very limited device availability. I really desperately want a 4 or 8 way relay device. eg: like wgldesigns' relay8 or the smarthome iolinc. I also really desperately want a UPB version of the Rain8. I could also use some in-wall 8-button controllers with lights (like smarthome's keypadlinc stuff).
Insteon:
+ Smarthome seem committed to produce a wide variety of devices.
- Hardly any are available yet. Even less than UPB.
+ switchlinc v2's have excellent WAF. Especially for our instant-on kitchen lights. She dislikes the lag from the SA UPB switches.
+ In theory, system reliability should improve as devices are added due to the mesh system.
- In practice, putting lone insteon devices on the far end of circuits with 8-10 X10 transmitters and no other devices to help them hear remote signals has been less than spectacular here. X10 transmitters and other X10 signal absorbers seem to like the taste of insteon carrier too and seem to absorb it as well. I don't have enough experience with this to be sure though.
+ In theory, adding more signalink RF repeaters should be an acceptable temporary workaround for signal void problems.
+ SALad and the programming environment for the controllers is very interesting. Now, if they allow SALad on more devices, not just the controllers... well, that would be really something!
- Relatively new and little track record in the real world.
- I don't trust smarthome's QA. I deeply distrust the smarthome designed devices after finding protocol bugs still in their late 2004 products. eg: cause three devices to transmit simultaniously and they lock up the X10 network forever, untill you power cycle them. (This is easy to provoke. Suppose you have switchlink-relay's at C1, C2 and C3. Transmit a grouped command like "C1 C2 C3 C-status-request" and BOOM! your X10 network turns to sh*t with 120KHz noise as all three devices try and yell over each other.) I deeply distrust how they'll implement and debug insteon.
- Insteon devices are not going to add reliability to an unreliable X10 system because they don't repeat the X10 signals. Backwards compatability is useless in an unreliable X10 setup.
- Insteon devices will degrade a working X10 system with few transmitters. All insteon devices are X10 transmitters and will suck away X10 signal, without repeating it.
- I dont see how Smarthome can deliver on their promise for a smooth upgrade of an X10 system without needing to replace devices. I personally fear that once you've got more than a handfull of devices, it'll be the point of no return and you'll be committed to replacing everything you can.
My bottom line is that for lighting control, I'm leaning towards replacing all the X10 switchlinc devices with insteon switchlincs. I can't live with the UPB double-tap detection delay. I could replace all the J-boxes, but the double-tap delay is the killer for us. PCS don't seem to care about problems like this. But for any equipment control, where reliability is critical (eg: floods due to missed 'off' events), UPB is my preferred system.
Hard wired signal systems (RS422/485 and friends) would be better, but it just isn't an option in this house.