2-3X the price is a bit of a stretch. Some quick comparisons: 600W decora dimmer (full # of scenes, full capability switch): Smarthome Insteon: $40 Worthington HAI: $52
Lamp plugin module: Smarthome Insteon: $30 Worthington Simply Automated: $56
Keypad: Smarthome Insteon: $60 Worthington Simply Automated: $79
Network reliability: Smarthome 2-pack SignalLink RF (recommended for all installations): $70 Worthington Simply Automated coupler: $53
The only one that comes close to 2X is the lamp plugin module. Certainly not 3X. However, if Insteon seamlessly integrated with HAI's OmniPro panels like UPB does (the biggest plus for me, personally), I would probably use Insteon as well.
Kurt