Whats the most quiet E-bike

That's pretty subjective, but I did have the opportunity to test ride a Bionx bike, and it was whisper quiet. Beautiful kits, but are very pricey.

I have experience on a Panasonic system and a Heinzmann hub. Of the two the Panasonic is quieter, and neither is very noisy.

If you want the very quietest type of e-bike, choose one with a hub motor that does not have gears. (Some hub motors like the heinzmann mentioned above have a motor that provides power through a gear reduction).

The golden motor and crystalyte type hubs, and a couple of other brands (wilderness energy, I think), are "direct drive" meaning that the motor doesn't use gears and turns at the same speed as the wheel. These motors are all essentially dead-silent and they look alike too - they hub will look large, 10 inches or more in diameter, instead of the ~7 inches or less of the gear reduction hub motors.

I believe all motors give the possibility of some electrical-systems noise, which depends on how high the throttle is and how fast the motor is turning. This noise is something like the sound a non flat-screen TV makes if it is muted.

Most, if not all ebikes aren't loud enough to keep pedestrians from stepping out in front of one. That's gonna be a big hurdle as infrastructure moves towards e-vehicles. Probably the most dangerous part of my daily commute - pedestrians not looking where they are going.