Generally speaking torque sensor is a more sophisticated technology which is getting a good performance and feedback on electric bikes such as those integrated with Bosch, Shimano or Yamaha ebike motor systems. Torque sensor should have an integrated engineering while designing the ebike. Bicycle dynamics affects the performance of the torque sensor, that makes it a bit challenging to get a smooth and responsive torque activated PAS for conversions. It actually varies bike to bike.
There is no torque sensor after market conversion kit available that truly performs better than our Motion sensor + torque emulating software. We have tested all options yet our cadence sensor is more accurate and responsive and feels more natural.
Torque sensors are more vulnerable and require more complex controllers which makes maintenance and service more difficult. At present we don't consider it a reliable and durable setup to offer in our products.
Torque sensors contribute in boosting your pedaling force, no matter how steep the road is, which means you have to pedal hard anyways if you climb a hill. Cadence sensor eliminates a certain grade of hills based on assist level selected, no matter how hard you push the crank, which means harder pedaling just makes it faster.