I think the DD hub motors shift smoother because they don’t put as much pressure on the chain and derailleur. That was my impression after riding a Stromer and a Vado back to back.Thanks for the info. I'm glad the BH Nitro City is a wonderful bike for you. My recent test drive of a Trek Allant+ 9.9S w/ the Shimano Deore XT derailleur left me unimpressed. How could a shifting mechanism so violent as to produce a loud "klunk" be reliable in the long term?