I've never bought a digital deluxe version, as it's 50% more expensive (45 euro's instead of 30), and I never really cared for any of the mounts/pets so far. If however, I can get a beta key for it as well, sign me up.
Edit: I think Cataclysm was the first expansion with a digital deluxe version? Or was I so not interested in it that I didn't even notice them before Cataclysm?