Crobat and Walrein seem to be the best recipients of the move. Crobat has a whole host of moves that it can use to great effect alongside Super Fang - Taunt, Roost, Whirlwind, U-turn - and I think it will be a massive threat to defensively inclined teams when paired with a Pursuit user (Weavile with his new Low Kick toy?) to remove Rotom. Crobat's decent defenses, great Speed, Roost, and Taunt in particular mean it can beat the vast majority of defensive Pokemon one on one with Super Fang + an attacking move.
Walrein is annoying enough as it is, but now it can do more than just stall for 32 turns. With the additional damage from the Hail and probably Toxic Spikes, Walrein will probably be able to easily destroy unprepared teams by itself. Remember that it has 110/90/90 defenses (much better than Swampert's) and recovers 12.5% a turn in the Hail. With Super Fang, it has very little need for offensive investment of any sort, and can focus its EVs on its excellent defensive stats to make it even harder to take down.
Nidoqueen is very interesting since it does a great job as it is of countering Lucario, can set up and absorb Toxic Spikes, set up Stealth Rock, and phaze with Roar. Super Fang might give it a considerable boost in usage. It also has access to Shadow Ball and Crunch to deal with Ghost-types that try to take its Super Fang.
This is all theorymon at the moment, but one thing I'm certain of is that Super Fang will have a profound effect on the way several Pokemon are played in OU.