When it's 3g there will be 4g, and when there's 4g there will be 5g, and when it's 5g there'll be..............
Not quite!
4G will be available shortly within 5 kms of the GPO in each city and ONLY for laptops (using a dongle or similar), not for your mobile phone.
For me, IPhone 3G:
2 bars and quality phone calls yesterday at 2,500ft on departure from Marree, outback South Australia.
Also yesterday whilst over Melbourne CBD at 7,500 ft, listened to all of my voice-mails without interruption for several minutes. If it's an issue with roaming over towers it sure as hell would have happened there yesterday!