[ddfu]

Usual half-explanation. The CTO works on behalf of the startup's investors, working towards efficiency, calculating performance metrics and revenue/expense figures and whatever else the guys providing the money need to see. This is an executive role.

The VP Engineering is essentially a management role, coordinating the company's product team(s) and ensuring they implement the CEO's vision. Ideally, the VP Engineering should be inspiring to his/her subordinates, but this is not strictly required so long as employees are producing.