Ampharos by a country mile. For starters, the normal typing really holds Dubwool back, having many weaknesses but no resistances. On top of this, Dubwools base stats aren't overly impressive, with Ampharos having a total base stat 40 higher than Dubwool. Ampharos also has the advantage of being able to Mega Evolve, which boosts its stats even higher and really gives it a competitive edge over Dubwool.