Andrew
Also, looking at the screen quality and verbal instructions, the best ones are
TomTom GO 720
TomTom XL
TOMTOm ONE
Garmin 760
GARMIN 255
Features they (almost) all have
Colour LCD display in landscape format.
Touchscreen.
SD memory card slot except the TomTom XL and ONE.
English spoken instructions plus at least another two languages to chose from
Options to calculate fastest and shortest routes.
Option of two or three-dimensional display of the map.
Display of car speed, distance to destination, estimated time of arrival, street names and distance to the next turn.
Day and night mode; in the latter, the screen changes colour and turns down the brightness so it won’t blind the driver when looking at it in the dark.
Points of interest: Schools, police stations, car parks, petrol stations, airports and railway stations. ATMs and hospitals.
What to look for
Data entry: Keying in your favourite addresses and points of interest (POI) should be quick and easy. Also, check to see if it’s difficult to use your fingers to select points on the screen or whether you need to use a stylus.
Memory cards: Memory cards (either SD or microSD) may contain the latest maps or can also store images, music and video files.
SUNA support: for live traffic updates, may be available via an antenna attachment, or could be built into the latest models.
Display: The screen should be large and glare-free, and show the information you want to see, such as distance to the next turn, current street name, time of arrival and distance to destination.
Some car GPS devices offer the ability to show rendered versions of popular landmarks as 3D objects. However, don’t expect your car GPS to suddenly render your trip in 3D just yet, with only major landmarks rendered so far.
Voice instructions: Make sure these are clear and loud enough to understand over car noise.
Installation and portability: Check how easy the system is to install and how easy it is to remove and carry — thieves are more likely to target cars where they can see a shiny GPS system through the window.
Check they allow you to store your home address and to select a location on the displayed map.