Get dad the gift that finds itself: a GPS nav system

Need guidance on buying a Father's Day gift? A portable GPS navigation system for dad's dashboard can be a tech-savvy option. Yes, we know that smart phones can reproduce many of the features of stand-alone GPS units, or personal navigation systems (PNDs). Guess what? PND makers know it, too, and in response they've slashed their prices while boosting quality. Models with large displays (4 to 5 inches), free map and traffic updates, and other advanced features used to cost $400. Now they cost half as much. Here are three good reasons to prefer a PND to a smartphone.

They're more reliable

A PND, unlike a phone-base navigation app, won't zone out for incoming phone calls or freeze up when your dad loses his cellular signal. (Though buildings, tunnels, and tall terrain can block GPS signals from any device.)

They'll save you money

Many smart-phone navigation apps update their maps by eating up precious data from the phone's plan. PNDs, on the other hand, are self-sufficient. They store their maps, points of interest, and other data onboard, and get their traffic data over an FM antenna.

They'll keep the lines open

With a PND, the map is always where it should be: onscreen and in clear sight of the driver. Meanwhile, the phone is free for passengers to make calls, send text messages, browse the web for Yelp! reviews, and so on.

Here are two winners we tested:

Find the right model for your needs and budget with our GPS buying guide and Ratings.

Garmin Nuvi 3597 LMTHD, $330

Though a little pricey, this slim, pocket-friendly PND is sleek enough to be mistaken for a leading-edge smart phone. And it's brimming with smart features, including local speed limits, traffic updates for secondary and tertiary roads, and advanced lane guidance to make sure your father is in the correct lane an upcoming exit. Its 5-inch display is among the best we've seen—especially in sunlight. And like other recent Garmin models we've tested, the user interface is easy to master while its detailed maps show the driver what he needs to see when he needs to see it. Another cool feature: The magnetic dock on the included windshield mount automatically and securely pulls the nuvi 3597 LMTHD into place, yet lets the driver safely dismount the unit with a simple tug.

Garmin Nuvi 3490LMT, $150

The Garmin Nuvi 3490LMT is an older premium model that you can now purchase for a fraction of its original price. Packing a very clear and sensitive 4.3-inch touch-screen display into a thin sleek design, it actually looks like an older iPhone (without the home button). Voice-recognition capability spares the user the drudgery of typing in new destinations, while the unit's multi-destination routing makes it easy to add several stops along a programmed route. As with other late-model Garmins, the unit's lane-assistance feature will show the driver when and where to changes lanes before the next exit or highway merger.

—Mike Gikas