I was previously with Optus but the network is hopeless.. data is almost non-existent, useless for skype unless you are next to a cell tower. Telstra are the best by far in terms of data speed and coverage. I use my iphone 4 to connect to the internet via tethering so no need for a dongle. Hotel/ motel can be very expensive in some places so I wouldn't rely on it. Skype is usually OK on my phone but the reception has to be good to get good quality. Data prices have dropped dramatically in the last few months.