I bought the Brompton 25 mile Version Pros -Great Value -Fits 2010 Brompton -Moderate experience required to install. -Configurable to set my desired acceleration -No speed limit power drop off aka the cliff. -It can maintain 16 mph. -Good customer support if you can visit their HQ in Hackney -10 miles on full motor assistance Cons -Cannot link Acceleration to Cadence -Requires conductive grease to maintain stable battery to motor connection -Does not come with a torque arm. -Pedal sensor requires a harder rubber support to stay put. -Battery requires wiggling to pull out of the hub -Battery does not charge iPhones