Depends on the situation. If you're attacking a fairly well defended possition, the Tiger would be better. Why? Because its 88mm has better HE rounds, and is better able to tackle dug-in possitions. In addition to this, its thicker side armor would provide better protection against flank shots, and thus enable the tiger to press the attack further than the Panther would be able to.
So, yeah, it would be a less effective tank when on a general offensive, but when you need to smash something up and break through defenses, the tiger is the tank you want.