TStoredProcs: .Open or Execute

I am currently using TOraStoredProc components for returning cursors to the client. Should I be using either open or Execute for the operation or does it matter which one I use.
Are ther any penalities for using one or the other

Rules of thumb:
1. If the stored procedure merely updates/inserts/deletes tables, but does not return rows, use Execute (though I think Open would also work)
2. If the stored procedure returns a result set, always use Open. You cannot use Execute and expect to iterate through the result set.