In photography, shutter speed or exposure time is the length of time when the film or digital sensor inside the camera is exposed to light, also when a camera's shutter is open when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time.
A high Shutter Speed will freeze movement but a low one will make it flow/blur.
The images above go from a shutter speed of 1/4000 to 0.4.
The photos above were taken with a shutter speed of 1/4000 this made the water freeze and they're darker as the shutter lets less light through.
The photos above were taken with a shutter speed of 0.4'' this made the water flow and they're lighter as the shutter lets more light through.
The picture on the left was taken with a higher shutter speed to the freeze of movement. The one on the right flows as it was taken with a lower shutter speed.
In my opinion the image on the left looks better as it isn't blurred and its much clearer to see the action.