Guys, I'm pretty sure all except Telstra are using the same basic speeds and network (probably from Telstra!).
I've had a vodaphone deal for 5G- $40 per month... really great, except when we moved to Ellenbrook and it fell out of 3G network and defaulted back to GPRS speeds (now back to dial up speeds- totally sucks!)
If you're in the 3G network (most areas- constantly expanding etc) these are great, if you're not sure- go Telstra.