[Tex/LaTex] the use case for the ucs package

Question

The ucs package (formerly aliased to unicode), provides support for Unicode as a input format, as I understand it.

Under what circumstances should I be using that package, and unicode symbols?

to my knowledge there has been methods for getting most (all?) symbols and accent into TeX since long before Unicode was devised.

Am I better of using the TeX facilities for that when possible,
and unicode when not?

Should I actually be using ucs all the time?

Answer 1

In the past a use case for ucs was when Greek input was needed; since TeX Live 2013 the situation has changed and full support for Greek input (monotonic and polytonic) is available with

\usepackage[utf8]{inputenc}

provided the greek or polutonikogreek is passed to babel.

Note that the package ucs and the utf8x options to inputenc are not compatible with biblatex and, while the ucs package has a new maintainer, it doesn't seem to be under active development (and it has several shortcomings, like the infamous \PrerenderUnicode).

In case some Unicode character is not available for rendering, you can always define a substitute for it with

\DeclareUnicodeCharacter{XXXX}{<code>}

where U+XXXX is the Unicode code point; alternatively,

\usepackage{newunicodechar}
\newunicodechar{<character>}{<code>}

does the same, not requiring to hunt through the code points.