The Navigon 5100 portable GPS navigation device has been generating marketplace buzz with its three-dimensional “reality view” graphics and built-in traffic receiver, but based on our initial tests it doesn’t appear to offer the same overall performance and value as models available from other companies. While the brand name might be new to American shoppers, Navigon was founded in Germany in 1991. It claims to have invented the first personal navigation product, and today it provides software for many other devices.

The 5100 has a 3.5-inch LCD touch-screen display, and it comes loaded with maps for the U.S. and Canada. We paid $550 for our test unit, though at the time of posting it could be found for $400 online.

Key features include:

Initial impressions. The Navigon 5100 provides good navigational assistance, augmented by interesting features, though it has not impressed us in the crowded portable GPS segment.

To turn on the 5100, you must press and hold the “on” button for about 10 seconds. While that might not seem like a long time, it can feel like an eternity when you’re in a hurry to hit the road. Several staff members were puzzled as to how to turn the unit on until advised of the protracted hold time.

We generally favor 3.5-inch screens for providing a good balance of unit size and readability. While the 5100 does have a 3.5-inch display, it is framed by a wide casing that is not as space efficient as some sleeker competitors. Further, the shiny metallic finish that surrounds the screen can cause glare in bright sunlight. And the text on the display itself is small and fine, which makes reading information at a glance while driving a challenge. The 5100 mounts to a long cantilever beam that can vibrate, like flexible boom mounts, which adds further difficulty to reading the display when driving on rough surfaces. Also, this mount might be awkward for vehicles with a steep windshield angle.

The 5100 has some graphical treats, such as the so-called reality view that provides a semi-realistic view of the road ahead, including road signs and exit ramps. Arrows overlaid on the road inform the driver where he needs to navigate, helping select a lane before a roadway splits. This is a useful feature when approaching confusing highway junctions, however this guidance only occurs when driving on the highway and not while driving around town.

The speed limit can be displayed with realistic sign graphics, which is a welcomed tool for traveling through unfamiliar areas, though the valuable information is not provided on all major roads. When the speed limit is available, speed alerts can further assist with adhering to local laws by signaling when the car is traveling a preset amount, such as 5 or 10 mph, above the limit.

The user interface has a friendly, high-tech look, but the controls are not as easy to use as with other competing units. The keypad for entering addresses is small, point of interest (POI) searching can be confusing, and backing up through menus is not as intuitive as with most systems. Overall, programming and function use can be frustrating, especially for a new user.

During navigation, the Navigon 5100 does a good job at providing adequate routing information, including text-to-speech for accurate street names. It is helpful to see the names of key businesses and municipal buildings displayed, as such landmarks can often aid navigation. An onscreen symbol indicates whether there is ZAGAT information available for POIs, such as reviews, business hours, attire, and approximate pricing. Another selling point for the Navigon is the free traffic service, with no extra hardware or activation needed. Many competing models offer traffic service, but require a monthly charge and sometimes an external receiver that adds significant cost.

CR’s take. The Navigon 5100 has appealing features that will grab shoppers’ attention, but there are better units available. Our top-rated GPS units have comparable prices, yet some add features such as Bluetooth hands-free calling, MP3 players, photo viewers, and video players. And more importantly, those units are easier to read and provide simpler control interfaces.

Learn more about in-car navigation. See our complete Ratings (available to ConsumerReports.org subscribers) on portable GPS navigation systems.