I bet San Fransisco is going to be at least as common in a yearfrom now as Helvetica Neue is today. Because when Apple says it's the best for screens, then so it will be for most designers.
Newbie here. What's the problem with Helvetica Neue?
See the article: "Ever since switching to particularly thin weights of Helvetica Neue in iOS 7, Apple has been chastised for using a font that emphasizes clean lines over readability, and San Francisco is intended to solve this."