Update 2: I've just tested a Kalkhoff bike with a Bosch Performance Line 65Nm, and the noise produced by that motor is similar to the Giant bike I recently tested. I can hear both motors, but the noise is quite acceptable, far less than the Bosch CX Gen4 which for me was really annoying.
Late August I'll be in Germany and will test the Vado/Brose bike as well, after that I'll be able to make an informed buying decision.