Current Cairo, as used by poppler's qt4 backend (should be patched as well), will default to FT_LCD_FILTER_LEGACY, since they removed cairo_font_options_set_lcd_filter(), which in turn results in hideous colour fringes.
First picture: poppler + cairo-qt backend to enable subpixel rendering. Terrible fringes because it defaults to the legacy filter.
Second picture: poppler + cairo-qt backend + cairo with this patch. Proper LCD filter, no fringes.
Further rationale for this patch can be found here: https://bugs.freedesktop.org/show_bug.cgi?id=10301#c95
On a side note, patching evince and poppler to also support subpixel rendering with the zhou13 patchset found here https://github.com/zhou13/poppler-subpixel would offer tremendous quality benefits, but I know how conservative distro managers can be when it comes to patching software.