Some people say that Star Citizen will be a revolution of Space Sim games and maybe even of all games, due to its complexity, gameplay freedom, interaction between players, etc... But so far all of it is only expectations, because the game has not yet been released and I believe that no one knows for sure when it will be.
So my opinion is that X Rebirth the best Space Sim released till now. The game brings together aspects that every fan of simulators and sand box games expect to find. There are no required path to follow, you do whatever you want and no matter what path you choose there will always be interaction and life in the game. When you really understand the game the immersion is incredible, you really feel like you are in a universe traveling between systems, galaxies, etc ... helping stations to fight pirates or even becoming one of them and attacking capital ships just for fun or to steal them and increase your fleet power, or even sell them and make lots of money... Anyway do what you think is the best for you! Build stations and start a corporate life, mining resources to produce all sorts of things, space farms that make synthetic meats, shipyard to build your own ships, etc... You can create and command your own empire, scattered throughout the universe...

But I admit that the game is not perfect, there are some aspects that I would like to be different. The main issue is that the game doesn't have multiplayer mode. This is a big mistake, because with all the in-game content I wonder how much better it would be if you could share all of it with another players... Like being able to create trade routes with other players' stations, make alliances to conquer territories. .. A game that is already quite alive with only NPCs would literally come to life in online mode ... Another thing is that you can only fly one single model of ship all the time... That sucks! Other than that, there are other minor issues that are easily fixed with mods.

So to conclude, if you like space simulators and look for a different game, immersive and with freedom. Play X Rebirth that you will not regret!

Fly safe!