Pretty much all working common System 11 games are above $3k USD now, except Jokerz!, Comet, Big Guns, and Millionaire. Police Force has creeped up to $3k and low $3k mark, same for High Speed, and I have seen Cyclone listed for low $3k. Space Shuttle and Space Station flirt with $3k, if it's a good player's condition. Jokerz! is probably the best System 11 value right now in terms of price and Pinside ranking.
I guess relatively speaking to the $5k and up premium titles, System 11 is still a good value.