The result is never satisfying for Minion Pro and lualatex. I manage to get a result close to perfection with the following MWE:
\documentclass{article}
\usepackage{fontspec}
\usepackage{unicode-math}
\setmainfont[SmallCapsFeatures={Renderer=Basic}]{Minion Pro}
\setmathfont{MnSymbol10}
\setmathfont[range=\mathup/{num,latin,Latin,greek,Greek}]{Minion Pro}
\setmathfont[range=\mathbfup/{num,latin,Latin,greek,Greek}]{MinionPro-Bold}
\setmathfont[range=\mathit/{num,latin,Latin,greek,Greek}]{MinionPro-It}
\setmathfont[range=\mathbfit/{num,latin,Latin,greek,Greek}]{MinionPro-BoldIt}
\setmathfont[range=\mathscr,StylisticSet={1}]{MinionPro-It}
\usepackage[tracking=true]{microtype}
\usepackage{xfrac}
\begin{document}
\[\sfrac{1}{2\pi} \quad \sqrt{3}\]
\end{document}
In that configuration so far the sfrac fails (missing /). If I exchange the line MnSymbol10 with MdSymbol then sfrac works but sqrt doesn't. I know this usage of MnSymbol is maybe not the right way to do it (just noticed $\bullet$ is missing also), as they aren't organized in regular with many number (5 -> 12) and I've no clue what it means.
Any idea how to get everything working?
