The AI is not "easy" to exploit, it is a bit harder than that. But not by much.
PBW is definately the way to go if your looking for a challenge, but PBW games are veeeeeeeeeeeeeerrrrrrrrryyyyyyyyy slow games.
I recommend finding a someone who can play a few turn fests with you and play a game over Instant Messinger. You can get up to 50 turns in a session.
