I wouldn’t pay more then 8 IPC’s for a tank or any other land unit for that matter. I personally would rather have a fighter for $2 more. As Nice as Tanks Are, They can’t attack Shipping. Planes are sweet also but they can’t take territory but they can move out of an area after a attack.
Planes have a total Movement of 4 and the tank, even with Panzer Blitz, is only a 3.
Hypothetically
Your Tank costs $8 and is a 4,4,2. (could even be 3,4,2)
No special abilities unless you are Germany w/ Panzer Blitz, and is restricted to land combat only
Your Fighter cost $10 and is a 3,4,4
Can Aquire Jet Fighters, can escort Bombers, and act as interceptors, can attack on land or in the Sea
Now comparing the 2 units side by side, IMO you get more bang for your Buck with airplanes as far as flexibility.
The H Tank is useful for putting up a nice Defence with out having to commit your air power to do the same job for $2 less dollars.
Each piece has it’s own Niche or roll to fill and are both valuable assets to any ones forces if used correctly.
Both of these pieces are useless without Boots on the ground though. In any attack or defense, Inf. are at the heart of it all.