The ability to drive your car around an unfamiliar city confident that your satellite navigation system will get you home is a modern miracle. The popularity of sat nav and the relatively straightforward technology mean prices are tumbling while manufacturers are resorting to gimmickry. We may soon see a model inside a dashboard-mountable stuffed puppy. If so, you heard it here first.

If you want a more straightforward sat nav then this review is not for you. Instead, take a look at InGear’s April review (see tinyurl.com/29fhmb), which recommended the best of the basic models. The five we have chosen this week are among the most advanced consumer models. They feature the latest SiRF Star III antenna (this picks up a reliable satellite signal quicker than older sat navs, even in built-up areas).

They also offer tools to improve a journey, such as speed-trap warnings and live traffic information. Many will even flag up points of interest, such as restaurants, and some boast speech recognition or trip meters that give the distance you have driven.

Our tests were designed to assess three things: how well each sat nav handled the fundamentals of routing; useful extras; and value for money.

Testing was conducted on a variety of road types, with two deliberate wrong turns taken. To establish if the maps were up to date, each sat nav was taken to a roundabout replaced by traffic lights in 2002 and a T-junction that is now a roundabout. Even though three of the models tested (TomTom, Road Angel and Navman) employed the same maps, results were mixed.

Ease of use was considered vital, as were concise spoken directions, and each device performed competently – although the Road Angel’s screen was sometimes cluttered. Where the wheels came off was in the provision of extras expected at these prices. Apart from the Garmin, all offer alerts of speed traps, but the Mio and TomTom do not say which side of the road the trap is on. Pointless really, as was the Mio’s indication of the speed limit, because it was in kph and sometimes wrong.

Another consideration was whether points of interest were enticing. Only the Garmin delivered a selection of genuine interest. The others tended to feature big chains, such as burger bars or bland corporate hotels, which gave the impression they were sponsored to do so.

Apart from the Mio, each delivered live traffic information. The Navman and the TomTom have a built-in free radio-reception feature called TMC. You simply plug in the supplied aerial, though TMC can be added to the Mio for £80. The TomTom can also receive traffic alerts via a Bluetooth mobile phone but there is a £40 annual fee for this. The Road Angel also charges a monthly fee, receiving its information (along with live speed trap updates) via a built-in GPRS data connection. The Garmin product is map software that runs on most smartphones and uses the data connection of the host phone. It was tested on an HTC handset with a built-in GPS receiver, and also with a BlackBerry using a separate Bluetooth GPS receiver (typically £40). Both worked equally well.

Aside from the Road Angel, all can make phone calls either to a number transferred from a mobile phone or to a place of interest, merely by prodding the screen. Useful for alerting a hotel of your late arrival. The Garmin integrated well with its host phones while the other three must be partnered with a separate Bluetooth handset.

When it comes to extra gizmos, the Mio doubles as a palmtop computer yet its sat nav features were the most limited. The Navman and TomTom are festooned with toys of variable merit. Gadget lovers will enjoy tinkering with them but it is hard to say they seriously improved the journey. The Road Angel’s trick of live updates will appeal to professional drivers and the Garmin offers convenience to smartphone owners.

JARGON BUSTER

Bluetooth Short-wave radio tool that enables some sat navs to work in tandem with most mobile phones

GPS receiver (Global positioning system) Element of a sat nav that receives the satellite signal and enables it to plot its location on a map. Usually built-in but can be a separate gadget for mobile phone based mapping

Live traffic alert A free radio service (often called TMC) that provides live congestion alerts to certain sat navs

POI (Points of interest) Useful nearby locations plotted onto a sat nav’s map. Can be directed to or often phoned by touching the screen

Speed trap locator Stores locations of speed traps and warns as you approach

SNAPPY SAT NAV

Navman S90i – typically £300 from www.ukstore.navmanstores.com

Solid sat nav, festooned with gadgetry

Navman’s swankiest model, the S90i is slim and, at 7oz, light too. It’s simple to operate and though it employs the same maps as the Road Angel and TomTom, the S90i was the only one of these three to pass either of InGear’s defunct-junction tests. The speed traps are directional, to indicate which side of the road a camera is on, and free TMC traffic information (see jargon buster) is a boon. The points of interest were plentiful, albeit geared towards hotel and restaurant chains. In truth, the Navman’s stiff price is due to fancy features. It converts inputted addresses to speech, boasts a trip meter that tracks mileage or average speed, and a 2Mp digital camera logs where a snap has been taken so you may choose a destination from a list of images. Modest value, then, but a treat for ardent gadgeteers.

Screen 4.3in

Traffic info Yes (free)

Speed traps Yes (1yr free, then £20pa)

European maps Yes

GADGET FAN

TomTom GO 720T – typically £329, or £310 from www.comet.co.uk

Tech lover’s treat, but costly and flawed

This svelte 8oz TomTom bristles with features such as the ability to choose a destination by you saying its name – which worked surprisingly well. The GO 720T uniquely boasts a built-in FM widget that can wirelessly beam directions or MP3 music (stored on a data card or 2GB of built-in memory) to the car’s radio. However, using this option prevents CD playback and the sound quality was modest. Despite these frills, the GO 720T retains TomTom’s ease of use and nicer touches, such as the way it zoomed into close-up as a junction approached. Unfortunately, it skimps on the basics: speed traps are not directional and the points of interest are dull. Traffic updates come free by plugging in the supplied TMC aerial, or via a Bluetooth phone for £40 a year. Big on fun, but overpriced.

Screen 4.3in

Speed traps Yes (£30pa)

POCKET ROCKET

Garmin Mobile XT (mobile phone maps) – typically £60 from www.garmin.co.uk/ wheretobuyauto

Class-leading mobile-phone sat nav

Smartphone owners looking to add sat nav to their handset should gravitate to this Garmin package. The Mobile XT is not a phone, but rather mapping software supplied on an SD memory card. It was tested with an HTC handset (pictured) that has built-in GPS, but most smartphones will work just as well if you add a separate GPS receiver. The software loaded easily and the menus were similar to Garmin’s standalone sat navs – a good thing. In use, the maps were clear, albeit cramped on a phone-sized screen. It calculated routes quickly and wasn’t flummoxed by either defunct-junction test. The Garmin’s points of interest are the best in the business and you can phone them. Free weather or traffic information is supplied via the handset’s data connection, though not speed traps. Despite too few spoken instructions, this gem is a bargain.

Screen N/A

Traffic info Yes (free)

Speed traps No

European maps No (£110)

CLEVER CLOGS

Mio DigiWalker P550 – typically £300 (with maps) or £289 from www.globalposition-ingsystems.co.uk

Competent palmtop with modest sat nav

Mio makes conventional sat navs but this is a petite (6oz) palmtop computer with a built-in GPS receiver. It runs Windows Mobile software and offers both wi-fi and Bluetooth, yet cannot make phone calls. The Mio was preloaded with the company’s own maps. Its GPS signal locked on well and the bright 3.5in screen proved nicely laid out for sat nav, albeit small. However, the speed limit symbol was often wrong and the speed traps nondirectional. They also annoyingly showed speed limits in kph. Unfortunately, the points of interest are listed by name rather than the far more useful proximity and biased to big chains. The Mio’s postcode search accepted only five-figure postcodes, and it failed both junction tests. A handy add-on for an occasional foray rather than a full-time sat nav.

Screen 3.5in

Traffic info No (£80 extra)

Speed traps Yes (1yr free, then £35pa)

European maps Yes

POWER DRIVER

Road Angel Navigator 9000 – typically £430, or £400 from www.nav-now.co.uk

Hassle-free driving info, at a price

Road Angel sat navs have a rich heritage of helping drivers avoid points on their licence. The 9000 does not need to be connected to a computer to update the speed-trap locations. Instead, a built-in GPRS data connection automatically downloads new details, plus weather and traffic information for a hefty annual charge of £69. You can plan a route on a PC and send this over the air to the device, or, for £48 a year, even track the gadget on a computer. The 9000 was more intuitive than previous Road Angels and it routed well, with clear instructions. The speed camera performance was faultless. However, the device failed both junction tests and the screen was occasionally cluttered. It’s also chunky, lacks Bluetooth and is exorbitantly priced.

Screen 4in

Traffic info Yes (£69pa)

Speed traps Yes (part of traffic info fee)

European maps No (£100)

Reviews by Dave Pollard

Prices include Vat and delivery