Thanks for all of the valued input so-far from everyone.
Paraffin Budgie, I had mentioned I would be buying an unlocked mobile phone, so the roaming you mentioned is not an issue as I will have networks in a number of countries. Pop in a local sim and data-charges become local charges.
The details you wrote about earlier re the smaller processors are good to know. Other handsets that come in both LTE and HSPA+ models have a large difference in size. Time will tell what the Samsung G S III differences will look like.
To others including Milo Minderbinder, with both the LTE and HSPA+ models announced to be available in the market by "summer" (an accidental snub to those in the southern hemisphere, too!!), the wait is not that long to choose both. The issue I see is the apparent lack of backwards compatibility of the LTE handsets to work with legacy carrier networks which leans the race more towards HSPA+ to avoid a lot of grief when travelling.
Now if only I can find a terrific deal out there for an unlocked, contract-free phone from the UK. Most "deals" of the Samsung Galaxy S III seemed to be tied to the 16 GB phone (and all the "WOW!" deals are gone, anyway). Any so-called "deal" for the 64 GB model hasn't appeared just yet.
Good thing I have some time off. Time to step up the searching...
Further comments / tips / assistance / deals appreciated!
Cheers,
RD