Melbourne based company. A few of my contacts use the soft phone and think it is OK. Don't buy any USB phone because they need a PC to be turned on and run the dialler. An Ethernet model is better if you have a router with its own dialler.
I personally use a US-sourced Vonage terminal which costs US$14.95/mth but you need a US shipping and billing address. My local phone plugs into it and answers to a US phone number. I also point a US 800# at it and it has been fun getting Bay Area telemarketing calls, surveys, wrong numbers, sometimes at 3 in the morning.
BTW, the voice quality at the middle position (50 kHz?) is adequate over my 512/128k ADSL provided I do no file downloading, else it gets choppy. Uploading a file renders the call unusable.
The Vonage can be placed ahead of the router, so that its QoS circuit can reserve some bandwidth and prioritise voice before other protocols, but it seemed a lot easier to plug it into the router.
To try and put it in a WW context, getting a US number can help Aussie sites that want to appear to be in the US.