The art of this manga isn't my cup of tea.
The stories are interesting enough. Although each chapter is a unique story, there is a conection with them all. Some characters and stories are developed in other chapters. There is also a sense of progression. As the story progresses, we can see the evolution of humanity in space.
The themes revolve around moral issues and human feelings. How can I forget the lonely AI sent into the deep space, the poor children on their uncertain journey or the brief but life long love in a blackhole.
I found it enjoyable. I don't like all the science talk, so I couldn't give it a better score. If you are into Science stuff, I think you will like it much more.