The main difference I worry about is that Sun recommends you don't use Vector any more. That kind of squashed my interest in the other differences.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi
Vector is synchronized (thread-safe) and ArrayList is not synchronized, therefore in most cases, when you dont need multi threading you wont use Vector because it gives performance hit (can be only accessed by one thread)