/TLDR; the app works fine, but the map is disappointing compared to the web version/ It's cool to have access to such official data, even more cool to enhance data by crowdsourcing BUT the map lacks some basic features (search bar on the map) and all the usefull filters available on the website (provider, network, coverage type,...).
A Google user
May 28, 2019
The app tries to get an idea of where you are but doesn't give the right upload limits. It provides a spike upload (example for me is: actual upload speed is: 4Mbps, result of this test: 45,6Mbps) this is just bad programming. (This holds true on my iPhone X 256Gb with iOS 12.3.1 and on my OnePlus 6 Android Pie 9.0.5 Oxygen OS). Please try to fix this. For now I'll stick with Ookla Speedtest.
Speed test and cell signal coverage measurement in a crowdsourcing application.