The TomTom 930 T, is slimmer than the round-backed devices of yesteryear, solid and well built. As portable satnav units go, the TomTom looks positively super.

TomTom barely has to do a thing to continue to be the leading brand in personal satellite navigation devices. It's therefore to its credit that it continues to find new paths to pursue and ways to make the navigation process as smooth as possible.

The latest model, the TomTom 930 T, is slimmer than the round-backed devices of yesteryear, and there's something reassuringly solid and well built about it. If other portable satnav units look good, the TomTom looks positively super.

It attaches to the windscreen using a stubby sucker that makes an audible sucking sound when you first squish it on to the glass. The TomTom 930 T itself has a small magnet to attach it to its cradle. When we tried to adjust the volume so we could hear the instructions, we found it detached a little too easily and, in the process, our passenger managed to inadvertently cancel the route.

The TomTom 930 T then decided it instead wanted to head home to London's Soho Square (where its PR company is based).

The standard female voice the TomTom 930 T uses to provide audible instructions is polite but firm and provides directions in just the right amount of time. You can adjust the number of yards you're given by way of warning before a turning from the default 300 yards if you wish. Street names are listed whenever you're in a residential area, while turnings on major junctions on faster roads show their overall destination as well as being announced.

Worryingly, the TomTom 930 T doesn't always get this correct, however. At a split in the M25 we were told to keep right and follow the M25 to Hastings; in fact we needed to keep right to take the A21 and not take the M25 at all. The first time we experienced this glitch we were confused by the device displaying a blue sign onscreen announcing the M25 to Hastings as where we should be going; contradicting both the actual road layout and the laning information displayed lower down on the TomTom's screen.

The laning information itself is very good and certainly makes things clearer at complex junctions – but the TomTom 930 T needs to be consistent in its instructions.

We could also take issue with a few instances of the TomTom 930 T telling us to bear right on sharper than right-angle turns and bear left when a whole new road was round the corner. The TeleAtlas maps clearing haven't quite got the measure of deepest rural Kent – or the odd junction in SE London.