Latex Backend: pdflatex vs xelatex

There are two possible LaTex backends available: pdflatex and xelatex whereas the latter is used by default. Here is a small comparison between the two backends (which is based mainly on personal experience; if there are others with differing opinions, then they are kindly invited to make the corresponding adjustments):

xelatex

• xelatex supports multi-languages documents, so it is easily possible to mix e.g. Russian with Greek and comment using standard Latin scripts. In addition, it produces a better looking text layout compared to pdflatex:

latex_elements:
    papersize: 'letterpaper' ## or 'a4paper'
    pointsize: '12pt' ## '10pt', '11pt' or '12pt'
    fontpkg: '\\\\setmainfont[Mapping=tex-text]{Linux Libertine O}'
    ...
latex_backend: 'xelatex'

pdflatex

• pdflatex is the classic processor for LaTex documents and it is faster than xelatex; plus it seems to produce better quality w.r.t. to "small things" (e.g. footnote labels are nicer looking):

latex_elements:
    papersize: 'letterpaper' ## or 'a4paper'
    pointsize: '12pt' ## '10pt', '11pt' or '12pt'
    fontpkg: '\\\\usepackage{libertine}'
    ...
latex_backend: 'pdflatex'