If you're looking to buy a dedicated GPS navigation device, you'll quickly discover that every manufacturer offers an almost dizzying array of products--each with slightly different features. The challenge, then, is to determine which features are must-haves and which would just be nice to have.
Of course, you must compare not only models from the same vendor but also models from competitors. While GPS devices share many similarities, their variations, as we discuss here, can help you make the best choice for your budget.
Screen size: Over the past several years, larger screens have been the trend for dashboard GPS units. Devices with a 4.3-inch screen have almost completely replaced ones with 3.5-inch screens. Any devices with 3.5-inch screens that you can still find are typically entry-level models, often with a limited feature set. Now, 4.3-inch-screen units are being replaced by ones with even larger screens. Devices in Magellan's RoadMate 3000 series, for example, all feature 4.7-inch screens, and the RoadMate 5000 series offers 5 inches. Similarly, TomTom's chart-topping XXL products (such as the XXL 550-TM), as well as the new TomTom GO 2505-TM, have 5-inch screens. And if you want a portable with a truly big display, Magellan's RoadMate 1700 has 7 inches.
Live traffic alerts: Among Garmin devices, those with a T in the model name include traffic alerts. In Magellan's lineup, all of the 2000, 3000, 5000, and 9000 series of RoadMate units include traffic, too. In both the Garmin and Magellan lines, the traffic feature is ad-supported--you don't have to subscribe to the service, but you will get occasional pop-up ads. TomTom's alerts, found in models with T in the name, are also subscription-free, but sans advertising.
Maps: Manufacturers have learned that consumers want to update their maps, and these days some models include lifetime map updates, generally available quarterly. Garmin and Magellan RoadMate models with this update feature have LM in the model name; TomTom models have M. Magellan's MU models receive a single map update during the life of the product.
The included map set is a key consideration, as well. Maps can cover not only the United States but also Canada, Mexico, and Puerto Rico. Some high-end models may have maps of Europe. Less-expensive units typically have less map coverage. If maps of Canada or Mexico are important to you, check the included map set for the device you are considering.
Bluetooth: Many midrange and virtually all premium navigation devices include a Bluetooth speakerphone interface. Garmin's works well with most phones and does autoreconnecting as well as reading contacts from your phone. And the Bluetooth interface on TomTom's new GO 2000 series works well with the Motorola Droid X phone. Magellan, though, is still playing catch-up in Bluetooth capabilities.
Text-to-speech: Virtually all devices except for the least expensive entry-level models now include this feature. (Text-to-speech reads directions aloud to you.)
Unique features: All the manufacturers try to add something unique to set their devices apart. Magellan, for example, offers a One Touch interface for single-tap access to favorites or stored searches. Some devices supply the AAA TourBook as well as a points-of-interest database. TomTom's IQRoutes is a routing feature that uses historical traffic data plus community-based map updates. And Garmin's newest Nuvi 3790 models have an ultraslim case with a multitouch, high-resolution 800-by-480-pixel glass screen that provides 3D building and terrain views.
Our Top 10 chart has links to each product's review.
We also reviewed four devices that didn't make the chart, as follows:
For all GPS products we've covered, see our GPS page.