Superior alternative to Arial
Ivan Bettger, writing for Typekit:
Designed originally by Örjan Nordling and later adapted into a complete font family by Göran Söderström, when FF Dagny was first released and licensed for the web, lamenters of the web-safe Arial soon recognized it as a superior alternative: a no-nonsense grotesque sans serif that reads better in body text while holding its own at larger sizes.
See also, the Alternatives to Helvetica list.