GPS navigation systems are getting more affordable every day, with powerful but basic units such as the Garmin StreetPilot c320 selling for scarcely more than $300. We got four higher-end GPS units together in the same place, taking them out of the road and comparing their capabilities. The crazy thing is, we liked them all. Check out our reviews of each one, and don't miss the oddly nightmarish video showing all of them operating at the same time, after the jump. – Charlie White

Cobra NavOne GPSM 4500
The NavOne has a relatively huge 5-inch 320x240 display, an easy-to-use interface and offers clear and accurate directions. It also gives you real-time traffic reports and lots of configurability. Type in those addresses with a QWERTY virtual keyboard, and it's off and running, telling you where to go with a sexy female voice. She doesn't know street names, but gives you plenty of warning when it's time to turn, rerouting you around traffic and telling you about 7 million points of interest. But the NavOne was cheap-looking with its plastic chrome trim, and bulky, too, at 1.3 pounds—certainly not one you'd want to carry around in your pocket. Even so, we liked it anyway. Don't be scared away by its $1000 list price, you can find one for $580 on the street, or spend about $80 less for the model 4000 without those handy real-time traffic reports.

Cobra NavOne Product Page

Mio C710 DigiWalker
This Mio GPS unit is the most versatile of the bunch we tested here. It not only gives you clear directions on its 3.5-inch screen but it's a respectable movie and MP3 player, too. Its GPS unit is highly capable, loaded with 5 million points of interest and a sensitive touchscreen that gives you a choice of four dynamic data sets at the bottom. It was the only unit in our test group that showed us our altitude, nice to know we were climbing some of the big mountains out West. In addition to its GPS capabilities, it also works well with Bluetooth cellphones as a caller ID device, and it has an unusually responsive dual-duplex speakerphone as well. It can also give you live traffic reports, but too bad its GPS unit doesn't work when you're using it with your cellphone. We also wish it had a QWERTY keyboard—it's Alpha all the way, which we find rather awkward. Even so, everything this DigiWalker attempts to do, it does well, plus it's highly portable and will fit easily in your pocket. It's $600 on the street.

Mio C710 Product Page

Honda Civic Hybrid Factory-installed GPS Navigation System
This one's built-in to the Honda Civic hybrid, and offers your choice of male or female voices, a huge 6.25-inch screen, and near-perfect interoperability with the Civic Hybrid's highly capable sound system which even has XM Satellite readiness. Its maps are upgradeable once a year, but the 2006 model has shown us a few blind spots on roads it should know about. A neat trick is its voice recognition, where you can push a button on the steering wheel and yell, "Go home!" to the dashboard, and its voice will politely ask you if you'd like to go home. It has a QWERTY keyboard and tells you how long until you get to your destination. Too bad it doesn't give you a choice of 2D or 3D maps, staying with 2D and popping up a close-up when it's time to turn. It's an option that'll cost you nearly $2000; see if you can haggle a lower price with that car salesperson.

Garmin StreetPilot c550
This was the easiest unit of the bunch to use, and although its voice was somewhat robotic, it actually made attempts at speaking the street names. Sometimes this was rather comical, but it came in handy. Besides giving you the most accurate and complete directions we've seen, it can also play MP3 files and sync up with your Bluetooth telephone as well. Its 3.5-inch LCD display hits the sweet spot between portability and large-enough size, and its touchscreen gives you just the right information, and it's plenty sharp, too. Its live traffic information antenna is integrated into its cigarette lighter adapter, and it smartly reroutes you around any traffic slowdowns or accidents. Too bad it also has just an alpha keyboard—no QWERTY here—but that was about the only flaw we found. Best of all, this Garmin StreetPilot c550 passed the ultimate test: I handed it over to my lovely but non-gadgety wife for an evening, and she and all her friends were able to use all of its features without instruction on a ladies night out, finding their way home without incident even through the fog of questionable sobriety. Bravo, Garmin. It's a pricey $700, but if you're looking for a cheaper unit with similar capabilities, consider the StreetPilot c320, a similar unit without traffic data, MP3 player and Bluetooth capabilities.

Garmin StreetPilot c550 Product Page

Take a look at this video, where you can hear the voices of all four of these units. The smooth-sounding male voice is that of the Honda Civic Hybrid's built-in GPS unit, the robotic male voice is the Garmin, the smooth and sexy-sounding female voice is the Cobra NavOne, and the other female voice is the Mio. – Charlie White