For my part, and I'm totally speaking as an individual here, I'm mostly using Z-Wave where I'd used Insteon before. Here are my reasons in no particular order:
- I find that Z-Wave sensors respond more quickly and reliably.
- While I'm no longer using them, I found that the Trane Z-Wave thermostats were more reliable than Insteon. I'll discuss what I'm now trying in a different post.
- There are generally more features in Z-Wave devices - well, some of them anyway.
- There is clearly much more selection in terms of devices given the variety of vendors making them. This also helps with price point - I can buy cheaper devices where appropriate and buy more fully featured devices that cost more where I need them.
- Associations (as discussed in another post) are almost as good as direct Insteon links - enough to satisfy my needs.
- For the longest time, I couldn't find an alternative to the KeypadLinc/FanLink combination, but Inovelli now has the Red Series Fan + Light Switch that is very similar. Aside from not having dedicated buttons for each fan speed, this device is pretty much identical in terms of the fan and fan light control solution provided by the Insteon devices. I have 2 installed already and so far I have no complaints.
- Dimmers generally go to the last brightness when turned on. This annoyed me to no end at first but I'm starting to be OK with it. Some of the newer Z-Wave dimmers are supporting a fixed ON brightness configurations - while it will work in Indigo it has some unexpected side-effects that we need to address in a future Indigo upgrade.
- As I noted above and in another post, not all Z-Wave devices are created equal - so while some may offer good features others may skip them. It's a bit difficult to determine before purchasing what things like this might come back to bite you. My recommendation is that if you're expecting some specific thing you might want to ask on the forums to see if anyone has experience with that particular piece of hardware before purchasing.
In my new home, I decided to go with the Inovelli switches because I liked the LEDs on them better (and I could set the color to basically anything). After getting one black series (lower-end features, cheaper price) switch to test with, I ended up going with the red series instead because it featured the notification feature which I think is a killer feature. Basically, it allows you to set the color, brightness, effect (blink, chase, etc) of the LED plus an optional duration (after which the LEDs will automatically return to what they were set to before the notification). This is going to be very handy in the future - I already have an emergency action group set up to notify every red series switch in the house to fast blink red whenever there's something bad going on (currently hooked up to leak sensors, but others will be added).
I also had 2 locations in my house where I had a 1 gang box but had 2 things in it I needed to control. In those two places I needed one dimmer and one on/off (relay) switch, and it just so happens that Zooz makes exactly that combination (the ZEN30). The LED colors are adjustable but they don't support all the fancy stuff the Inovelli switches do. But they work really well where I need them.