I try to use unicode-math
with Linux Libertine, and the result is in general working fine. In my opnion, the main problem is fractions. Consider the below example where there is far too much space above the horizontal line. Is there a way to fix this?
I know that Linux Libertine is not intended for use with math, but it might be that this particular issue could be solved.
(BTW, I compiled my document using LuaLaTeX.)
\documentclass{article}
\usepackage{unicode-math}
\setmainfont[Ligatures=TeX]{Linux Libertine O}
\setmathfont[Scale=MatchLowercase]{Latin Modern Math}
\setmathfont[range=\mathup]{Linux Libertine O}
\setmathfont[range=\mathit/{latin,Latin,num}]{Linux Libertine O Italic}
\setmathfont[range=\mathbfup]{Linux Libertine O Bold}
\setmathfont[range=\mathbfit]{Linux Libertine O Bold Italic}
\begin{document}
\[
\frac{27}{81},\qquad \frac{\pi^2}{6}
\]
\end{document}