I was trying not to show any pictures of the giant spaceship I am working on but I failed. This skybox is really scenic and an instant favorite of mine so I just had to take a picture of a build including it. The Nebula skybox is something you experience rather than look at, and is going to become the default skybox on my development server for this spaceship.
I would say the only con is that lighting should be unique. As the default lighting
(note: not the lighting in the picture, the lighting used in the image is slate lighting.) feels as if you are still on earth where as it should make you feel like you are in the enviorment. However it is not difficult to change those settings so the lighting is not a considerable turn off. But if you need a space themed skybox, I would highly recommend downloading these.