Darnish Energy Agency and Nordic Telecommunication Administration in, took the responsibility of conducting an independent test for the 26 most popular phones in the Nordic region. The test result showed that Lumia 640 and Lumia 650 is a better phone in voice and data signal strength compare to iPhone 6S and it's peers.
Anyway, Lumia 950 didn't seem to be lucky in the test, and practically not from the expertise too, acting as if not of the same breed with the previous two. It ranked really low on the list, yet not as low as the Apple phones.
Prof. Gert Pederson; after carefully looking into the results, suggested that Phones should be labelled with their antenna performance rate.
Source: MSPoweruser