mate i just bought a pair of new mk3s...
i used to own mk2s and i would see absoloutly no reason to upgrade IF you already had mk2s (new/decent ones) but mine were really old and i felt i needed new decks. If you are in the position to buy new turntables the way i see it is that if you shelling out ALL that money and your decision is mk2s or mk3s... you may as well pay the extra 30 bucks or whatever it is in the us and get the mark3s even if not for the features or something just to hold its own in value you know if your shelling all that out you may as well go that tiny bit extra and get the shit!.
sorta make sense? anyway whatever you choose. enjoy there both great decks!