I'm with 3 via an optus $19 plan.

I have NEVER been on Roaming, I live in Tullamarine, Melbourne, and often frequent to the city, and many other areas around Melb. So it has not been an issue for me. If I were to go into a roaming area, I would just turn off my auto email fetching. And if I really needed to use the internet say for e.g. GPS - Maps, I would simply replace my 3sim with my optus one, and bam 100mb to use on optus (3g or 2g).

Other benefit with 3:

Setup your 3 email account (free) and basically get visual voicemail. You get an email which then says who it is from (name, not just number if they are in your address book) and then simply download the audio file. Pause and re-wind as you please...much easier than normal VM. PLUS! I have been advised that this service is free!

ONLY drawback that I have noticed, Unlike other carriers, all 3 handsets have MMS support, so they therefore do not provide a service for handsets that do not have this capability. So unlike Telstra and Optus customers, there is no friendly sms with an internet link leading to your MMS.

Once again you have no idea what you are talking about.