Here's a single formula to show star rankings (including half stars) for anyone who's interested:
=IF(ISBLANK(Rank@row), "", IF(Rank@row = 0, "☆☆☆☆☆", IF(Rank@row = 0.5, "⯪☆☆☆☆", IF(Rank@row = 1, "★☆☆☆☆", IF(Rank@row = 1.5, "★⯪☆☆☆", IF(Rank@row = 2, "★★☆☆☆", IF(Rank@row = 2.5, "★★⯪☆☆", IF(Rank@row = 3, "★★★☆☆", IF(Rank@row = 3.5, "★★★⯪☆", IF(Rank@row = 4, "★★★★☆", IF(Rank@row = 4.5, "★★★★⯪", IF(Rank@row = 5, "★★★★★", ""))))))))))))
Font size: 36 (Arial); Color: yellow
Fully functional on reports and dashboards!
Enjoy!