I do agree that this font look greats on the Iphone, according to this article http://www.wired.com/gadgetlab/2012/12/new-gmail-hands-on/
the font used is the same than in Google+, and it appeared to me that it is Arial font. It is surprising to see how nice it looks in this app. Very thin but very easy to read.
Fuseau horaire : CEST. Il est actuellement 18:55