[drewal]

Let's use my level 38 necromancer as an example...

The advantage lies in having a greater repetoire of spells available, and he's got just about every spell in his book.

If both spellcasters were equally skilled, they would be able to neutralize each other for a good period of time. But during that time, the mage would learn what spells the sorcerer has available, and rememorize-wish-rest accordingly. The sorcerer cannot do that.

The necro can summon anything, cast any offensive spell, cast any defensive spell, the sorcerer can't.

Since the sorcerer is limited, the necro will be able to block what needs blocking, and attack where the sorcerer is weakest.

The adaptability of the mage outweighs the brute force of the sorcerer.

The brute force of the sorcerer will take anything else out.

In the end, it would really come dowen to who fails a save first.