Well, as you are probably aware, Apple rarely, if ever, pre-announces software updates. So, no-one outside of Apple knows if, or when, iSync will be updated.
It is rumoured that the imminent 10.4.9 update includes updates to iSync, but there is no word on what these updates are, or whether any specific phones will have support added.
Apple are actually encouraging third-parties to make iSync Phone Plugins for phones, so that you
don't have to wait months for the next update from Apple to use your shiny new phone.
All software is unknown until you try it. As the developer of the afore mentioned Plugins, I can assure you that I have many, many satisfied customers, and provide fast and free support if needed.
If you want some reassurance, read all the 5 star reviews at
VersionTracker.