The biggest thing holding satnavs back in this country has been a lack of real-time traffic information. Even though Intelematics launched the SUNA traffic channel in Melbourne last year, the other capital cities haven't had the same luxury.
It looks like all that's about to change, however. I received an invite to the official launch of Sydney and Brisbane's first real-time traffic information service. It's an extension of the Melbourne SUNA offering, which is currently supported by most of the major satnav providers (albeit via an optional extra antenna, in most cases).
They're also promising to announce some new local partnerships at the launch event, which happens on August 13. We'll be there, so stay tuned for updates then.