People make a lot of the engine being on or off. In actual use online you turn the engine on when you want to align with a target, and then turn it off. It's the same as a Tiger II in that regard. So for defense it should be the same as a Tiger II, easily out maneuvered and attacked with superior numbers, despite being slightly faster.
This tank is an ambush tank, and an assault tank. Because the tank has a limited traverse it is likely the perk cost will be slightly less than for the Tiger II. The questions I have concern reload times, and elevation of the main gun. The HE rounds are superior to the 75mm of the M4A3, obviously. However, if the reload time defeats the superior power of the gun, then its assault strength is bested by the M4A3-75 (which I have always said is the best artillery tank in AHII - and probably of WWII).
With all of the factors considered you might think (as some have already said) that this tank will be a hangar queen almost immediately, and that HTC is catering to the kiddies and WoT patrons. While I partially agree (the kiddie part at least) I don't agree about the hangar queen status.
Outside of these thoughts I will reserve judgment until the tank is actually in the game.