I've had my Dahon Speed TR with DualDrive for 3 years now and no issues what so ever (Over 1,500 miles). I think the dual drive is the perfect drive for a folder. Given the short distance from crank to rear dropouts, a chain has to deflect a lot to go from a three cog front to a rear cluster. The Dual drive eliminates this deflection since the front has only 1 cog center on the rear cluster. Add in the ability to shift at a standstill and no front deraileur alignment issue and the Dual Drive is the unit to have on a folder. In fact, it was on of the key components that help me select the Speed TR
Brian