It's fair to arrange spec work competitions as long as you don't give out false pretensions about the rewards going to the winner and you find the risk of inferior results acceptable.<p>The reverse version illustrated here is ok on the same grounds: as long as the author does not promise anything to the contenders she won't deliver, it is fair game.<p>But the difference is obvious. 99Designs <i>works</i>. The reverse doesn't.
I don't get all the whining about 99Designs. If you don't like it, don't use it. It's not like it's going to turn good designers into bad designers, or make companies that used to hire good designers hire bad designers instead.