I am a little late to this thread...
I have been a big Insteon user and developer since the products initial release. After 4 years of having Insteon in my home, I am ready move on. The primary reason is reliability. The iterations of the devices over the last 4 years has still not resulted in reliable and robust products. In my home, I have 45 Insteon devices (ranging over most of the various devices). As of last week, I have now replaced 42 of the 45 original devices. Only 2 Switchlincs (the very first ones released) and 1 KeypadLinc are still working. I have had to replace many devices due to the infamous failure of the paddle design. Many more have have been replaced due other various hardware failures. Many existing switches (that I should replace) require you to press the paddle in the exact right spot to get light control.
Like many things in life, the cost of entry is only one part of the equation. SmartHome may be cheaper to get into but you will pay in the long run with the headache of constantly replacing devices and relinking/reprogramming your HA controller. I would not recommend their solution to anyone.
I am not sure where SH went wrong with their Insteon implementation of the Linc line. At one time, I had many of the old X10 Switchlincs and KeypadLincs which lasted for years and years with very few failures. I moved to Insteon with the promise of greater reliability and 'speed' and more sophisiticated lighting control. It has not been worth it.