I find this very usable on my iPhone G3, and have been able to use it very successfully in Sydney, the Blue Mountains and even in smaller towns five or six hours out west, such as Condobolin.

The maps have proven accurate wherever I've used it, even without the TomTom cradle that I bought to go with it. The cradle seems to make things faster and more accurate (and even though I'm not really reviewing it, it does a very good job at turning the iPhone into a hands-free). My old NavMan was terrific (until some mongrel stole it), but at times it could park you anything up to 100 metres from where you needed to be. So far, the Navigon usually parks me right in front of my destination.

I like the clarity of the screen and, although I find it a bit irritating because it stays up for a bit longer than I feel I need, the display of the overhead signage on the freeway, showing where to exit or which lane to be in, is helpful.

In a complex bit of software like this, and without a manual (and to be honest, I haven't really checked to see whether there is one on a website somewhere), I find the setup options not always the clearest. But that doesn't really detract from the usefulness of this app, which is now indispensible.