The Tiger is a fearful vehicle, a huge behemoth of a tank. It is dreadfully expensive to produce , but it's capable of dominating the battlefield with it's 88 mm cannon if properly supported. The only real weaknesses it has, are that it is a bit slow, and the tracks are vulnerable to mud and cold. In the early years of war, there was no Allied cannon which could penetrate the front hull of the Tiger.
Panzerkampfwagen VI Aus E Tiger on Wikipedia

KwK 36 cannon:

With a higher-power gun than the Panthe's KwK 42, the KwK 36 was capable of firing an 88 mm round. In fact, in the early years of WWII, the KwK 36 was the only German tank gun that could penetrate the front armour of the Soviet T-34 tank. Additionally, the accuracy was such that the KwK 36 enabled the Tiger to perpetrate first-round kills at over 1200 metres (A Sherman could only destroy a Tiger from it's back at 500 metres.) in combat.
Calibre - 88 mm (3.46 inch)
Maximum Velocity - 2536 ft/s (773 m/s)