The devices report a screen size that takes pixel density into account, so the reported resolution is a lot lower than the actual screen resolution. To force the issue, add the following meta tag:

<meta name="viewport" content="width=device-width">

(Other solutions are out there, but it all comes down to playing whack-a-mole with the reported resolution.)

Edit: never mind the lower. My S3 actually reports higher than actual. But the meta tag works to trigger the 479 media selector.

PS
I think MSSmartTagsPreventParsing can be taken out behind the shed now ;-)