Re: difference between use of Repeat Control and Datatable in xpages.
The repeat control is more flexible. If you have not yet read Mastering XPages, buy a copy. It will answer many of these questions. There are also a number of training resources like TLCC's free course as well as paid courses, NotesIn9.com for free videos by IBM Champion David Leedy and others as well as xpages101.net for subscription-based videos by IBM Champion Matt White.