Not sure what all the hate in the reviews is all about. The UI has totally changed and I guess thats hard for established users. I think that most of the complaints are probably user error - the maps do pinch in and out, you can edit trips, the large plane icon is only there on the trip info page and not on the map page, etc. No longer syncs with TripIt only Expedia which is also made by the same developer so no surprise. There are some known bugs and limitations that are noted in the help pages.
I find it reliable, easy to use and having the most data of any flight tracker app. And it does look nice! Its one of the few if not only app that distinguishes between leaving or arriving at the gate and actual liftoff or landing.
Peterpw about FlightTrack 5, v5.3.2