You know, the adapter is expensive, but it's worth the dough for a great connection. You could also think of it like: two controllers to play w/ two friends is a hundred bucks, but adapter connects you with the world for the same price. If the quality of the adapter were spotty, I'd say it's not worth half of full price, but it really works well.
EDIT: I forgot to add, I'm on the second floor of my house with one, and my router is downstairs behind several walls. Perfect connection.