Mio's DigiWalker 720t GPS unit is a slight upgrade to the DigiWalker C520, but it adds a 2-megapixel camera for geotagging photos and comes ready for the TMC (Traffic Message Channel) service.

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Mio once again uses split-screen technology on the C720t -- the display is split 70/30 with the largest view dedicated to the navigation map, and the other 30 per cent displaying additional information. These include the current time, speed and date, a list of the nearest POI's, traffic information (to be launched in Australia in 2008) and a list of the next four turns in your trip. We found each of these had a significant and positive impact on the overall navigational experience.

The Mio Map menus are a mixed bag. The main screen is excellent, with clearly labelled icons and a text description, but some of the submenus feature smaller icons with no text. The lack of labelling also occurs on the map screen, so icons are small and confusing.

The maps themselves are impressive though and our experience was positive. Mio uses Sensis V14 mapping, and these are preloaded onto the unit's 2GB of memory. An excellent feature is the automatic zoom, which hones in every time you make a turn to give you the clearest possible route.

The C720t is equipped with the popular SiRFstar III GPS chipset and it takes anywhere between 15 and 30 seconds to pick up a GPS signal. The overall navigational experience is pleasing thanks to clear voice instructions and the text to speech technology works quite well -- even if it does struggle with some longer street names. Our only complaint is the fact there is no external volume control.

When searching for a specific address, the C720t doesn't filter suburbs by state, so you are presented with a list of every suburb in Australia. Once the city is selected, the street name, filtered by suburb, can be chosen. The address entry screen uses an on-screen keyboard and you can switch between standard, QWERTY or extra large layouts.

The usual routing options, such as avoiding tolls, unpaved roads, motorways, ferries and U-turns are all supported. Users can also set a preference for using motorways or normal urban roads, while up-to-date speed camera and red light camera warnings are also included.

The C720t has an audio player, photo viewer, a contacts list and Bluetooth for both handsfree calling and music streaming via A2DP. While handsfree is a handy addition, we sometimes struggled with clarity of calls so it isn't effective as a dedicated handsfree speakerphone. Multimedia files can be stored on an SD or MMC card. The C720t also comes ready with a TMC cradle and antenna -- the TMC service is set to launch in Melbourne in December 2007, while Sydney and Brisbane will follow in mid-2008.

A 2-megapixel camera is also included, and it also doubles as a video recorder. Photos are automatically Geotagged (provided you have GPS reception) and saved to the 2GB of internal memory. They can then be used as a waypoint in the Mio map application, or uploaded to sites like Google Maps.

Unfortunately, the implementation of the geotagging functions is less than impressive, as taking a photo requires you to exit the Mio Map application altogether. The menu icons are small with no text and the lack of labelling makes the entire process extremely confusing. The camera also doubles as a business card reader but its performance is ineffective overall.

The C720t's battery lasts up to four and a half hours according to Mio figures, which is satisfactory, but not outstanding.