As the pending arrival of the iPhone 4 next week (July 30th) and the re-availability of iPhone 3GS 8GB in Hong Kong, the Apple mobile carrier partners, 3 HK and Smartone-Vodafone (SMV) have began to compete in tariff plans.
The only difference between the two plan; from an iPhone user point of view, is the extra 100 free inter-network voice minutes that 3 HK includes in their plans. Both have a 24 months contract commitment.
One very important note to be aware of, is SMV's ability to transcode most Flash video to enable them to be playable on the iPhone while using SMV's 3G network. Such capability is not available to other carriers in Hong Kong.
Note: as a reminder all iPhone sold through official channels are SIM-unlocked, meaning SIM cards from any GSM carrier can be used inside.