I personally say Greedent , since it gets more coverage moves than Dubwool does. In fact, Dubwool is worse than Greedent , having lower base attack stat by 10 in exchange for better defences.
Looking at the level up moves that they both have, their strongest STAB are Body Slam and Double Edge, both learned at level 20 and 50 for the respective Pokemon. Greedent also gets Bite and Bullet Seed while Dubwool gets the inferior Double Kick and Reversal. In their TM/TR section of the moves, Greedent gets Dig, Rest, Thief, Protect, Facade, Bullet Seed, Mud Shot, Payback, Assurance, Every Elemental Fangs, Round, Tail Slap and Brutal Swing, Sword Dance, Earthquake, Superpower, Crunch, Irontail, Hyper Voice, Substitude, Seed Bomb, Wild Charge, Psychic Fangs and Body Press while Dubwool gets Thunder Wave, Rest, Protect, Facade, Bounce, Payback, Round, Retaliate, Sword Dance, Body Slam, Agility, Substitude, reversal, Baton Pass, Wild Charge, Electro Ball, Zen Headbutt and Body Press