Matt,
There are some threads on this site with pro's and con's and opinions of the mobile co's in HK.
I agree with Shoegal re 3 network, or any of 3G services - wait till they are better equipped. If u want reliability, stick with GSM/2.5G phones for now. in saying that, 3 has some cool fones at good prices, but not really sure how cool the coverage is in HK (and i dont think it will work in US??? i could be very wrong here though)
The more popular networks are better re voice quality and coverage. Someone gave a comparison in a previus thread, but in essence i think SmarTone, Sunday and CSL GSM services were the top ones here.
They all have deals from time to time, check the websites. they dont offer free current phones on plans or free weekends/after hour calls. they do come with bundled minutes in their plans. generally SMS to same network is free, and a cetrtain amount of minutes per month is free to same network, and another allowance for external network. once again, check the deals out.
For roaming and reliability, the bigger companies are better, as they have more deals internationally. I personally prefer SmarTone-Vodafone, only cos I have never had rpobs with the service in HK or abroad. But they don't necessarily have the best deals all the time.
In reality, the airtime etc in HK is so cheap compared to Oz (and i assume US) that it is really not a huge issue what deal u get, if all u want is a mobile to talk/send messages.
http://www.hkcsl.com/main.html
http://www.peoples.com.hk/p_homepage_iso.jsp
http://www.sunday.com.hk/portal/main/index.jsp?lang=en
http://www.three.com.hk/website/page...x.jsp?lang=eng
I'm not sure which HK companies offers dual numbers on a SIM. i know some phones are capable of this (u can choose to be on line 1 or 2, but not both simultaneously), but not sure which networks support this, nor costs...
the unlimited Sunday to Sunday thing u saw was most likely SMS, not calls.
hope this helps!