In my campaign as Pontus, I destroyed them after driving the greeks out of annatollia. They didn't put up much of a fight, the only problem was that immediately upon victory, the Egyptians came right on up and declared war on my weakened forces. This, combined with the plague, is making for a very long fight. The Seleucids are very dead now, however.

They don't really interest me, their starting position is too wide and unfocused. The main reason I play as the small factions is that I don't like starting off with large chunks of territory, I like to gain it on my own terms.