Ok, so I've had a chance to fly my Mavic with the official DJI Mavic ND filters. I'm not a photographer and I just like flying my drone with decent non edited pictures and videos, so this is from a noobie point of views.
Initial thoughts:
The filters come in a small box, similar to thy propeller blades. No case and no cloth bag, just 3 filters wrapped in individual plastic inside the box. None of the filters have any markings so they don't say which is the 4/8/16. The filters seem to made from plastic.
The filters are easy to clip on, and seem quite sturdy when placed in. They can be put on before turning on the Mavic and before doing the gimbal initializing. They were a bit tough to take off as you need to unclip them from the camera, and I didn't want to pull too hard in case I damage the camera or gimbal.
In the air, they seem to do their job. Again, I'm not a photo person so I can't give a professional opinion, but they did add a layer of shade during bright days, similar to sunglasses.
I can make an unboxing video and an in flight video if you would like.
