Does anyone have experience of using an unlocked UK dongle to allow sim cards with US data bundles on? The idea is to be able to connect to the web using the dongle and just purchase sim cards for the countries we visit. Sounds too easy I guess. Any help would be appreciated.

In my limited experience, they work where the local service provider lets them. In Fiji in particular, Vodafone is the dominant provider of v cheap, access but the Sim refused to work using our Dongle, it comes with some software that makes it work forcing you to buy the dongle. It 's not much more than $10 so no hardship.