I think for this new technology this is an impressive list of working airports. Like I said before, my original experiences gave very poor results (not tracked, tracking on another continent, brand new Duracell batts DOA, and so on). Lithium batteries would work longer, but they are more expensive and prohibited on flights.
Did you sign up for the lifetime service when it was offered a few months back? They (he, Harry) is offering this lifetime service again for USD 40 until the end of this month (Sept 2015). I'm just hesitant to put $40 out if the batteries go dead in a few hours; no reason to expect that would change ...
Other opinions / perspectives would be welcomed. I think I would love this if it really worked and I was an excited early adopter when this was first announced.