if a vector has the same price as a Verge ..I would take the Tern...
If it has the same price as a link I would def take the Dahon ...
Frames and forks are expensive , howver the components are really what drives the price up ... i.e you get far better components with the vector than with a Link ....
yes the tern frame is stiffer than the regular dahons, the vector frame gets awful close though. And it is debatable if you really can feel the difference in day to day riding . Its almost like having a car with 330 hp versus 350 hp .... can you feel the difference ? I sure don't and I have raced cars for years. ( don't ask.... the older I get the better I was )
thor