Forget the last installment (X:Rebirth). This is the absolute crown of the series.
Amazing depth, complexity, moddability and visuals, this Ship of the line of the X-series puts you in a truly captivating and immersive universe for you to explore. I've spent countless hours back before on non steam version with simply exploring systems as I searched for lucrative trade opportunities and keeping an eye out for hostile presence on the scanners, but if you want to do mission, bounty hunt, build or pirate, you have all the opportunities.
My favourite of the X series. The interface might be a bit intimidating first, but you can soon get used to it and it truly feels like a complex, scriptable ship computer, again adding a bit to the immersion and the tools it offers to the player in commands and mods are endless.