I think the Panther was the better tank. Faster, it's gun was just as good as the 88 in taking out any known armor.
Once they got the teething troubles fixed it was a better buy for the money. Even with it's weak side armor from up front it was hard to kill.
AS much as I despise the name sake of this tank, I would argue that the IS-2 (Stalin-2) was the best heavy tank of the war.
http://www.wargaming.net/tanks/MODELS/js2.htm
120mm frontal sloped frontal armor
122mm high velocity cannon.
max speed 37km/h
hieght of 2.73 meters.
It ate Tigers for lunch. King Tigers were their equals, but the Soviet design was more reliable adn produced in larger numbers.
Of course tactics count. In the 1967 War, the Israelis used upgraded Shermans against IS-3's and won.