I don't like the look of this ```if``` statement. Again something a styleguide would prevent you from writing.  

But because of ASI the first conditional should be on the same line as the ```if (``` and the second conditional should really be moved into a variable above to make it easier to read and comprehend. I.e:

```JavaScript
var notGettingHintedFonts = !(guardian.platformsGettingHintedFonts.test(navigator.userAgent) && !guardian.platformsNotGettingHintedFonts.test(navigator.userAgent) );

if(config.switches.webFonts && notGettingHintedFonts) {
    // do stuff
```

Although our Uglify process during compilation would squash this and my ASI worries, its good practice to make your clean.