The thing is, much like ED, the fans basically rushed the development team, and they released a game that wasn't quite up to their standards, under fear of losing people. A Year after it was released, it has become a great game, though still straying from the original X-Series roots (Single Ship, more defined story). But definitely worth it now.
But X3: Terran Conflict is your best bet, comes with most(all?) of the DLC(Think of a GotY Edition). I was lucky and picked a physical copy in a Dollar Store! Sank many many hours into it.