First and foremost, I have enjoyed the previous X titles immensely, however, this product does not deserve a good or even mediocre review.
Do not reward developers and studios that push badly designed games which are near broken and often unplayable. It is quite obvious this game is not ready to be released and even if it was bug free, there is so much wrong with its design and art direction that it feels like an indie game made by people with absolutely no talent what so ever.
Lets put one thing on the table...space is amazing. Nice visuals, quite varied in looks....but thats were the good ends. From the ship, to the actual characters... it is ugly, and not just in the subjective way, but in the way in which objects and characters look like they belong on the playstation 1. Low poly, stiff characters that are poorly rigged and poorly animated. Mouths are not synced to words and for some reason space seems to be inhabited by old bald women with scars on their face. In otherwords, most NPCS are the same exact character model and its hideous.
The controls are bad, non fluid and jumpy. Environments (interior) make no sense and are poorly designed visually and layout wise. I dont think Egosoft has an experienced level designer. The interface is non-user centric, it fights with the player and you really dont know what you are seeing half the time.
Lighting is inconsistent, poor, and clearly baked.
Previous X games, each ship was its own object. Space was littered with them. In Rebirth, most of the ships you see are fake. They dont exist as a normal game object like other ships, they are there to make you think space is more active than it really is. They do a poor job at this as well.
Bugs bugs bugs. The game is broken in so many areas and on so many levels. Performance is very very very very BAD. Say you have a powerful gaming rig, well guess what it probably wont matter because the game will refuse to run like every other game.
This may very well be the end of the franchise, its just that bad. Avoid at all cost and wait to see if it ever gets redeemed. It needs to be remade.