Before you jump into a mobile tariff contract (for 2 years or 15 months) with your new iPhone 3G or iPhone 3GS you need to understand that not all 3G (HSDPA) network are the same. This is especially important if you are going to buy a new iPhone 3GS.
The reason is because, unlike the iPhone 3G, the iPhone 3GS is capable of supporting 7.2 Mbps downlink and 5 Mbps uplink speeds. At the moment as far as I know the 3 HK HSDPA network is capable of supporting 3.6 Mbps downlink speed at most locations and 7.2 Mbps at certain locations. Where as Smartone-Vodafone’s HSDPA network is already capable of supporting 14 Mbps downlink at every location.