Thanks everyone! I'd seen that some folks in this forum liked the Downtube. No one in my immediate vicinity sells them, so I haven't been able to look at one in person. Dahon's I've seen, and Brompton (I do like these, but also very expensive), and Bike Friday, I've tried those but they are pricey. I've heard about KHS but never seen one or heard about anyone who had one. I would go for used, if anyone knew of someone in the Philadelphia area with a decent folder for sale...