X3 is a very different game from this. Its a lot of fun but its 3d combat and the AI is much worse than this game.
It's similar in some ways, you can capture ships, buy and trades stuff and outfit your ships as well as command you fleet from your "flagship"
You never know this game could become similar once fully developed
this game will never be like X3 because already in version .35 the ships fly better than X3 does in version 1.3 or so. The ways they are similar are that they're in space you have ships you can trade and fight.