My tip to using Google fonts, or maybe any custom fonts, is to include the following within the head tag, to ensure everything looks as consistent as possible across browsers.
<style>
html {
-moz-osx-font-smoothing: grayscale;
-webkit-font-smoothing: antialiased;
font-smoothing: antialiased;
}
@-moz-document url-prefix() {
body { font-weight: lighter !important; }
}
</style>