Wikipedia should be considered a good source, but you need to be aware of when it could be good or bad. The more popular your topic is, then the more will it be revised by the wikipedia team, and the less popular, the less chances it will. So depending on the "popularity" of the topic you can decide weather it is a good source or not.
I would like to state that it wasn't forfeit, what I did, that is. We merely had the same line of thought and it so happened I thought I was pro and he thought he was con, when really, no side had to do any convincing of the other.