Stellaris is great. I had been eyeing off a lot of space 4x games before it came out, and I have been very happy with my choice. Also, I know some people hate their DLC strategy, but to me it refreshes the game every few months. Only problem is, your saved games become unplayable. So keep up to date with the dev diaries to know when a release is coming, and consider turning off auto-update until you are finished your run.