Not worth it. . .
I live 10mi from an airport, this app cannot seem to locate any plane that is at any angle higher than 15deg from the horizon (i.e. anything remotely overhead, within several miles), so its pretty much useless. I contacted the developer on twitter, no response. I understand there is a (small) delay in ADS-B, but thats not the problem here.
rymacguy about
Plane Finder AR