Remark -- The answer given below addressed the original version of the posting, which asked if there's an advantage to using \ldots over.
The difference between \textellipsis and \ldots is, that the latter can also be used in math mode. It is defined as (from latex.ltx).
\cdots: The \cdots command produces a horizontal ellipsis where the dots are raised to the center of the line. \ddots: The \ddots command produces a diagonal .
LaTeX question: How do I create an "ellipsis" with LaTeX? Very simple, if not intuitive. Wherever you want the ellipsis to appear in your LaTeX.