Waze performs surprisingly well when you have no signal during your journey - I guess that it pre-emptively downloads the bits of maps that it knows it will nee

Waze performs surprisingly well when you have no signal during your journey - I guess that it pre-emptively downloads the bits of maps that it knows it will need. OTOH, Waze is next to useless when trying to first pick a route when you have anything less than a great signal. 2G or patchy 3G? No hope. The dumb app will just give a timeout error after about five seconds or so and refuse to even consider plotting a route. It's like the developers never bother to test their code on anything other than a perfect internet connection.