Navigation is very easy indeed. The default screen shows a 3D view of your location and you simply tap the screen anywhere to bring up the menu from where you can select the navigate menu to route straight to your Home location, to a saved favourite, a recent destination, or to a post code. You can plan in advance so you don't need an active GPS signal for work out a route in advance, and as the entire maps are located on your iPhone, you don't need a data signal to start with. Despite the large data set the app starts up relatively quickly on an iPhone 3GS in less than 10 seconds.
In use, we found the routing to be effective. The app also takes advantage of TomTom's IQ routes, which draw data from thousands of user journeys and as such you'll get the most effective route for the time of day. The apps also warned us of approaching speed cameras with a chime.
When an incoming call is received, the map disappears to be replaced with the phone screen, but audio instructions still continue from the speaker. When the call ends, the map auto resumes.
We read many complaints of the position indicator on the TomTom app lagging behind the actual location, but we didn't experience this in our tests. Recent updates to the app may have helped in this regard, and the SirfStar III chip in the car kit appears to be doing its job.
While we found ourselves perfectly happy with the usability and performance of the TomTom app, we were frankly surprised at the lack of features compared to standalone devices. With the x40 Live series in 2008, TomTom added the Google Local Search feature that enabled you to find where you wanted to go via a Google search, and then route to it. It seems like a no-brainer to include it in a data device such as the iPhone, but surprisingly it's not present. As such, you're limited to using the included Points of Interest database, which while comprehensive is clunkier than a simple Google search.
