My 2 cents: Donating helps the server, but donating isn't everything.
Questing is fun, believe me, I've done it tons of times. What my fellow GM's have said is true, you can obtain donation items through questing and hard work. Donating just gets them to the players faster.
In the end, it's all in the skills. You could be a top donator but couldn't kill a kitten, or you could be a badass questing guy and be able to battle your way through everything thrown at you. The end choice is still yours.