Just curious, have you ridden and compared the Bosch to Brose and Shimano? If so how did you feel it compared in resistance?
I currently have a two bikes on demo, a Bosch powered one, and a Shimano powered one. I'm also due in just a few weeks time to take on a totally unrelated bike that I'm not currently allowed to discuss. I did have the good fortune to ride a Brose powered bike for the second time this evening during our weekly group ride though, and being a very high spec Levo, it was never really going to disappoint.
Noise wise, my opinion is different to what is being claimed, but I have already mentioned elsewhere that tone, pitch, cadence, assist level, frame material, and riding conditions all play a major role in 'perceived' loudness for each DU. Without correctly calibrated noise testing equipment, people's opinion including my own, of what is the quietest, is completely meaningless and irrelevant. I would stick my neck out and say that for the most part, comparing the three DU's mentioned, that for 70% of the time, that the Brose DU is quieter than the Bosch. There are climbs and cadence where it isn't though. As said though, without controlled conditions and test equipment, it is all meaningless. I have also ridden some Bosch powered bikes, that have left me wondering if the motor is even running, and others that leave no doubt of it. Weird how even between DU's of the same brand and type, that differences appear.
I would agree that the transition from assist to non assist is more linear on the Shimano and Brose DU, but in the case of the Shimano DU, I'm not overly keen on where it produces torque against cadence. I haven't ridden the Brose enough yet to format an opinion about that, but as the owner had used the app to alter settings, it wouldn't have been easy to gauge.