May I first comment on the first thing I spotted on this page, which (for now?) is the poll?
So far showing only 3 brands (Samsung, Becker, Pioneer). This is misleading and also limits the choice too hard. But the choice will be expanded as the numbers of posts grow, I think.
E.g. I have a 5" Motorola Moto G (2015) smartphone running NextGen smoothly and IMHO it meets every possible criteria mentioned higher including it is cheap.

Shouldn't the poll not be more general like "Smartphone, tablet, handheld, inbuild"? Am I missing a possibility? Second the OS (Androis, WinCE, IOS, (dedicated?))
One then could specify a specific device in posting. This could be a long thread
Oh, and when not build in the car/truck, how it is fixed in the car could be interesting to know as well.

As for "proggy" I guess that discussion will be endless as well. Osiris already gave wonderful information, but forgot google maps, Waze, HERE we go, MapsMe, .... just to name 4 of many. Then the choice for off line or on line maps, speedcams (e.g. AFAIK not on HERE), information on screen (e.g google doesn't show current speed, needing an extra app like velociraptor) traffic information, speed of map updates (just watch how quickly waze reacts on changing situations like 1 way streets), ....


This could be the beginning of a very long discussion thread.

Just saying.