Love that someone has extended the phenomenal underscores theme to be responsive out of the box. This theme also provides an excellent solution to the gnarly nav issue on mobile.
As a front end developer, this saves me a lot of time. Not sure what the "awful spams has included" comment was about as there is absolutely none in this theme.
I used m1 to build a test site and it's working great in the ones I tested: Chrome, FF, IE, Safari, ipad, iphone.