Does iCloud sync through wifi or 3g?

Either. Syncing is via Internet so however you are connected that's where sync takes place.

This is not a reply.... which is the PRIORITY if both are possible ?

No answer, so that likely means if the carrier wants the phone gives priority to cellular. So best to jail break the phone so the user has control ?

Priority to any Internet access is always give to wifi if you are connected to a wifi network. It will obviously use cellular when there is no wifi. You can also control some iCloud syncing through cellular through Settings/General/Cellular/use Cellular Data for: .

Thanks Stephen, That's the information I wanted to hear. 🙂