As you will know there are hundred's of different types of GPSs, Car, handheld's, For the boat, Pilot GPS, they tend to come in series's.
IE: 200 series, will incoperate all the 200 model's 260, 205W, 200 etc...with little variation's from one to another, but until you go up a level, they generally are the same, wider screen, odd different user option, but generally, the same series, has the round about same specification's, checkout the stores for the little variation's of each device, in the same series.
Below is a list of the different Model's that I have gathered a few together for easy comparison, and my view of the product from a repair and solution's point of view.
Hover your mouse over the type of Garmin, then click on it to check this one out !!!
Garmin Nuvi 200 Series
Garmin Nuvi 300 Series
Garmin Nuvi 500 series
Garmin Nuvi 600 Series
Garmin nuvi 700 Series