When I got bitten by the GPS bug, I decided to compare GPS systems to see which would be the best for me. I only had a vague idea of what these remarkable devices did. I knew they were essentially electronic maps, but I had no idea how they worked, or what was important to look for when buying one. So, I decided to do some research.

My first stop was Amazon to check out their best sellers. (Just click on my link below to see the same information.)

I quickly saw that Garmin, Magellan, and Tom Tom dominated the market. Garmin, I had heard of Magellan and Tom Tom, I had not heard of. My elation at seeing who were the best sellers for GPS units was soon crushed by an overwhelming sense of confusion as I clicked on each item, read its description, and tried to make heads or tails out of the differences between the units.

There must have been some pretty big differences, I thought, because the prices ranged from a low of about $150 to almost $1000 for portable units-the kind you can stick to your windshield and remove to take with you when you're out of the car.

Well, suffice it to say, I did an enormous amount of research and became an expert of sorts.

To save you some time and frustration, let me tell you the basics of what I found out.

Although there are several manufacturers of portable automotive GPS systems, the three main ones are Garmin, Magellan, and Tom Tom. Garmin sells about half of the automotive GPS systems in the world, but Tom Tom is quickly catching up. All three companies make a good product, it's just that understanding the differences between the three manufacturers and their specific products is a little difficult.

Garmin has two main lines of automotive GPS systems, the Nuvi and the StreetPilot. The functionalities of each line overlap quite as bit, so does their price.

In general, the Nuvi's are sleeker, more compact units. Their interface (how you use the system) is not quite as straightforward as the StreetPilot's interface. Garmin Nuvi's come in a broad price range, from less than $200 for the Nuvi 200 to almost $1000 for the Nuvi 770. Per price point, Nuvi's generally have a few more features than StreetPilots.

The main difference between the Nuvi's and the StreetPilots, however, are these-according to Garmin, Nuvi's have a high-sensitivity receiver, whereas StreetPilots do not. Nuvi's weigh about half as much as StreetPilots. (None of these units is heavy, just StreetPilots weigh almost 10 ounces, where Nuvi's weigh slighlty more than 5 ounces.

The biggest difference between the two units is the user interface. The StreetPilot "c" series was made expressly to be very intuitive and user friendly. This is not to say the Nuvi's are not, they're just not super simple, like the StreetPilots.

Tom Tom has devices that directly compete with Garmin's. The Tom Tom One, for instance, is comparable to the Garmin Nuvi 200, Garmin's entry level product. Both are basic GPS systems which come pre-loaded with maps, have touch screen, and voice instructions. The Tom Tom One has a battery with only 2 hours average life, where the Nuvi's battery will last an average of 5 hours.

To my mind, the Tom Toms are not quite as sleek looking at the Nuvi's, although their quality seems to be comparable.

Magellan does not have the market share of Garmin or Tom Tom, but they still build a good product. The Magellan Maestro 3100 is a big seller on Amazon. In both price and features, it's comparable to the Tom Tom One and to Garmin's lower priced units, both in size and weight. Magellan says their battery lasts up to three hours, fifty percent better than the Tom Tom's.

One of the biggest differences between the cheaper GPS systems and the more expensive ones is the number of "Points of Interest" in the unit's database.

Points of interest are preloaded hotels, restaurants, business locations, hospitals, basically anywhere you might like to go, which are included in your devices database. The Magellan Maestro, for instance has 750,000 points of interest. The Garmin Nuvi 200 comes with approximately 6 million!

If you're going to use your GPS for traveling, having more points of interest available might be a key feature, and when you consider the distances involved, 750,000 items is just not that many.

Another feature I think is important is Bluetooth technology. Your higher priced units can work as a cell phone (both making and receiving calls). It's hard enough (and even illegal in some areas) driving and talking on your cell phone. Add looking at your GPS to that mix, and...well, you might want to pull to the side of the road. To my mind, the fewer devices to keep up with the better.