Bike Friday makes some nice bikes. A little weird looking, but good quality and designs.

I know a guy who is an airline pilot, so he travels a lot. He folds up his little bike and takes it on the plane with him. He took 5th place in the 24-hours of Adrenalin SOLO class last year in Monterey. Then he went to the World Championships in Whistler, B.C. and he won his class.

In Monterey he did a few laps on a Bike Friday, but at the World Championships, he had to do the whole race on his "big wheel" bikes. But he says that he did about 70% to 80% of his training on his little fold-up cycle.

I have never heard of the Dahon, but there are some quality made fold-up bikes out there if that's what you need.