Proof that handling trumps engine size. 
Two very different design philosophies though showing just how *Different* you can make simple two strokes behave. The Suzuki, although using Ernst Degner's ideas, was always meant to be a robust, softly tuned, comfortable, tool with bags of midrange torque. The Yamaha was a much more hard edged device with porting and a reed pack that was made to deliver a blistering top end at the expense of bottom end and midrange.
The 400 was the last of the air cooled Yamahas and the precursor of the RD/RZ 250-350LC's. Undoubtably one of the greatest motorcycles of all time.
Pete