Figured I would post my controlbyweb experience since the thread is/was about the X410. I've got my X410 up and running 100% to my liking. It did cost a bit all together, but it's so much more than boiler monitoring. Hopefully some vacation time is in my future and being able to keep an eye on humidity, temperature, and water leaks in the house is a major plus. I've got the thermocouple adapter with a 4" probe in my flue, it works quite well, and the ability to have the thing email and text my phone if something goes beyond my custom parameters is awesome.
I did find a bug, in the coding apparently, and this week they were very willing to help diagnose and rectify the issue. There is a bit of a learning curve to overcome, but if you like automation, this system is slicker than owl snot.