Comment by adrian_b

Sans serif fonts are preferable only on low-resolution displays (this includes 1080p) or at small point sizes, because in this cases the good serif fonts cannot be rendered correctly.

The classic serif fonts cannot be rendered correctly at low DPI not only due to their serifs (which must be enlarged at low resolutions, to avoid their disappearance; this transforms all classic serif typefaces into uglier slab-serif typefaces), but also due to their "contrast", i.e. because they have both thin and thick lines (which are equalized in width at low resolutions, distorting the glyphs). Some of the better modern sans serif typefaces, e.g. Optima, also cannot be rendered correctly at low DPI, due to their variable-width lines.

On high DPI displays, the preference for sans serif or for serif is driven mainly by the familiarity with the tested typefaces, so it is impossible to predict from the results of a half hour test, where the people may see for the first time some typefaces, which of them they would prefer after using them continuously for six months.