Recording "White Christmas" without being Bing Crosby is kind of like recording "The Christmas Song" without being Nat "King" Cole: treacherous, fraught with automatic comparisons. This doesn't stop anybody in either case. Enter Michael Buble, doing his carefree/less crooning thing to the track and previewing it for the world more than two months in advance (and yet less in advance than the Bieb. Oh, scheduling.) All we can say about his contribution is that it's what you either love or don't about Buble's music; unless Buble's withholding some serious WTF for the full track, you won't find any drastic departures.
You might find a departure in duet partner Shania Twain's voice, though. YouTube has apparently juuuuuuust figured out that Shania Twain's voice doesn't sound like the Mutt Lange-armored growl of her past albums. What they haven't figured out is that it doesn't sound much like her voice on "Today Is Your Day," either. In fact, it sounds kind of like Madonna's, quirks and sass built in. In this case, that's a compliment. Maybe her future work will be awesome after all!
And yes, we know it's still October. We're sorry.