The lens is good in low light, the focus is fast and accurate. For low light it absolutely needs some form of camera support. IS would help a lot if you don't plan to use a support.
Neither IS nor support will help with a moving subject. In the "Disney Dreams" image you can see Mickey's and Minnie's hands are blurred due to motion. The only thing that will help with this is the f/2.8 lens.
I tread lightly on most of my images, these have little processing. Prints look about as expected, very sharp if you can hold the camera still. This is a very sharp lens and any image problems are likely to be from movement, not from the lens itself.