What Car? guide to portable sat-nav - Garmin StreetPilot c510

Cost £269
For Screen is clear and simple to interpret
Against A bit too bulky
Verdict Easy to use, with a good screen

Although too bulky to be carried in a pocket, the Garmin c510 is our favourite overall as it's a great unit at a bargain price. The menu was one of the easiest to work out and we reckon that you wouldn't even need to read the manual to get going. The layout was logical and self explanatory, yet despite the simplicity it was easy to find the more advanced options. We also found the screen clear and the easiest to read, even in bright sunlight, and liked the simple colourful map and fun cartoon car indicating the route.

Your time of arrival and distance to next junction are clearly shown in the bottom corners and are easy to read at a glance. The view alters as you approach junctions, helping you get a better understanding of their overall layout. We liked the simple instructions written at the top of the screen, rather than just the name of the next road — for example, 'Left on St. John's Road'. Our route diversions were handled efficiently and the Garmin quickly worked out the next best route and continued to guide us. Full postcode entry was quick and easy, but if we didn't have the postcode it wasn't hard to find a location by town and street address. It was also easy to find Points of Interest.