As for NCR's coverage of Globe Telecom - which I am using, here is what Open Signal provided.
Here are a few information that Open Signal provides:
WIFI singal strength
Map of nearest cell tower/s within your area (turn on your location to activate)
Direction of the nearest cell tower where you are connected
It also gives you information reagrding connectivity statistics (see image below), upload and download speeds, which is somehow similar to the ones that speedtest.com provides, data usage (downlaod and uplaod), calls (made and received), text messages (sent and received), percentage of the time that your connected (on wifi and on data), and coverage map that shows signal strength (per network provider or both).