Uhh... well, it's totally different from the X series.
It only shares the name.

It is less complex and offers less options, but might be more accessible to newcomers. I personally love X³ - Terran Conflict, but I still like the visuals in X Rebirth. It's just that I miss being able to fly other ships (because in Rebirth you have only one)

I'm glad to see it get here, but to be honest the best thing has already happened, since we now have X3:TC and X3:AP on GoG.

X: Rebirth only allows you to fly a single ship. It's true that it is an upgradeable ship, so you do have the novelty of some RPG-ish elements added to the game, but it's still a single ship.

But what about being able to personally fly in a gazillion of ship types, from ultra-rapid scouts to overpowering capital ships and switch from one to the other at your discretion? Well, that's gone. Yes, simply gone.

You can still command a gazillion of ships and ship types, but not fly them personally even if you're inclined to do so.

That, in my opinion, was a BIG step taken in the wrong direction for hard-core X universe fans.

I'm quite happy with my M1 ship garage and the extensive ship collection that it holds in X3:AP.