What GPS System Features do I want or need?

To answer this question we must first look at what is important to you.  In my opinion the two most important things are:

1. the screen size - standard sizes are 3.5, 4.3 and 5 inch.  4.3 is about right - not too small and not too big.  You want it big enough to be able to see it easily but not too big that it is a distraction.
2. text to speech - the GPS should call out specific street names rather than simply say, "turn right in 100 yards", etc.  This helps you keep your eyes on the road.

Other features you may want to consider:

* = NEED     /    + =  a'Plus' but not needed

x = not necessary

Amazingly, there is no monthly fee on most models.  There may be a fee for updates (annually, etc.) 

Let's look at the three types of GPS units.  First of all, the 'handheld' GPS unit...