Is there any negative sides of using the silent mode on the ronin? I was wondering, because it makes a lot less noise when in silent mode, and if there are no downsides, I would use only silent mode on the Ronin-M

It's a"Ronin", you supposed to walk like a Ninja, so silent would help. But seriously, the reason why it makes a hum is for the operator to know that it's working because most of the time, we don't look directly at the Ronin, we are too busy trying to frame our shot and looking in front of us.