I've just lost my third game in a row to someone solely because said person paid for extra features.
One could stack up to 29, which turned a potential stalemate into a crushing win for him, the other one had a special race and could stack up to 39, and the third one could stack up to 29, but the last two games were mostly easy wins for them, the racial bonuses came in play only in the very end, as a way to kill me without giving me a chance to fight back.
Non-paying players need something to compensate. A way to earn similar bonuses through XP alone perhaps. As of right now, I feel like hosting games and kicking everyone who I know is a paying player, as these bonuses are strong enough to turn fun into rage.