I tried the Yamaha system today at Eurobike. It's quite nice, but it's certainly not Bosch. It's an excellent option at a lower price point, but Bosch remains the premium drive in my eyes. Some features are nice, like the option of using a chainring and I like that the lines are a little more streamlined.
I feel the Bosch system is smarter, it can better predict your riding style and adapt to it accordingly. For example some riders want to ride in the high range of the gears and ride really hard while other prefer to find a cadence that works and adjust the gearing to maintain that, I feel that the Yamaha drive fails to adapt in this scenario and overall it just feels cheaper. Someone earlier referred to it as Bosch is the Audi or Porsche, where Yamaha is the VW GTI, although Yamaha isn't German so I would probably group it more closely to Honda or Nissan.
I was trying to understand why on paper the Yamaha looks to be the winner (price, torque, added chainring, etc), but after riding the two one after another, I select Bosch. It's a feeling thing. I have always spoken highly of the sensing technology of the Bosch system, it's really what separates them from others, just think of the resources and assets they already have on hand from the extensive R&D in automotive, appliances and power tool applications. Much of this translates well into the ebike drive system.
I think there's a huge market for the Yamaha drive and I'm excited for them to come to the states, but I want to make the distinction clear in case some were wondering. I certainly was.
