Need folding bike for commute <$400

I have a slightly hilly commute - 11 miles each way - to an office in a building that is bike unfriendly. I'm looking for a workhorse folding bike with a rack for this commute that is under $400 - firm. Right now I'm split between a used Dahon P8 coming in under $400, and the Downtube 8s (with...