Product review (4 stars): Monitors temps well and you can check it from your iPhone - I like it
It's a little tough to set up - and the UI is not entirely intuitive on the iPhone app - but it works as designed.  I'm running three sensors that are 1 -2 floors away from the base unit and it all works fine.  It's great to be able to monitor these temperatures from an iPhone from wherever I am home or remote.  It'll alert you if it loses connectivity.  I couldn't find where you can set temp limits by sensor (or at all) to send you an alert (that would be great).  You'll need a good, stable wifi.  If you have that - this works as advertised.