I started with X10 in the late 80's and then in 2014 I discovered the wonderful existence of the ISY994i, which allowed me to evolve to a few Insteon devices. Unfortunately my Insteon PLM broke soon afterwards and then I decided to experience with Zwave. Eventually my whole home became Zwave, dropping Insteon.
Of course I realize that Insteon is the core of almost all ISY-Polisy-Eisy users but the IOX programing and the out-of-this-world customer support of UD kept me, even with only Zwave, and of course I evolved to Eisy.
The stength and weakness of Zwave is that there are multiple manfacturers. That means that one is not dependent on one source, but it also means that the quality and features between products can vary significantly. I often heard the criticism that Zwave can be slow, especially when different devices are linked (such as a virtual 3-way). However I discovered the Zwave Association feature and that makes this immediate, just like with Insteon.
While I have Google Home and Alexa throughout our home, and use voice control, and also use my Iphone, I am more of a computer guy with 3 computers in the home. That is where I discovered Home Assistant which allows me to keep HA open all the time, unlike IoX which is not made to keep open contimuously. With @shbatm 's ISY Integration I had the best of both worlds. Over time I added Zigbee and numerous Integrations to HA and, because I no longer have Insteon, I ported all my devices to HA.
However for all you Insteon users the news that HA can now be added to Eisy is excellent news. You get HA but also the IoX programing and more than anything the top UD customer support. There is zero customer support with HA and only the forum.