>I have a single DBF, where several records need to be updated independent of the rest of the database. However if all records are not updated successfully, then I need to revert the all changes.
>I can achieve this with BEGIN TRANSACTION ... END TRANSACTION or with Table Buffering.

with table buffering you cannot. then ...

>Which alternative is recommended and what is faster?

no alternative.

>Note that ideally, I do not want to lock the table during this process.

this is impossible.