I just did an Insteon installation for a friend. It's my first Insteon experience.
The project's fairly small right now, only about 25 switches/dimmers plus a few appliance modules in a 3500 sq ft house using a Mac and Indigo to control them.
I priced the insteon/icon solution vs. X10 for them and the prices were almost identical (maybe a few bucks less for insteon) when I included the phase coupler/repeater, etc.
And, what a breeze to install!
The Icon and Insteon switches and dimmers are wonderful to work with compared to X10 modules. They're significantly smaller so there's less fighting to get them into the boxes.
I'm not a Mac guy, but doing the software was a no-brainer. Like ALL the home automation software I've used for lighting, its UI is quirky and it's a little clumsy to define lighting events, but it works fine. Set up is nothing. You just give it the hard-wired addresses of the Insteon devices, it finds them and voila! You do want to keep a spreadsheet of the locations and the addresses of the insteon devices so you don't have to run around looking for which device is where.
They've been running for a week or so now -- 100% reliable. If it was an X10 installation, I'm sure I'd still be tweaking it (older house, main plus 2 sub-panels, lots of "junk" on the power line...).
I'll be doing a larger installation in the next couple of months. It'll be interesting to see if the same experience holds.
Mitch