The X series has been a blast from the past of sorts. The series closest to the true glory game, Elite or Frontier (Elite 2).
The problem I found with the entire series is that it has too many bugs and problems. Whilst the game may look stunning, much better than current FPSes imo, the combat in it doesnt fit properly, stitled and slow... AI has pathfinding issues, engine is usually poor and a strain on a machine...
Its excellent for a flashback but you just wish that they'd nail down a decent combat model and sort out the engine/bugs. Cutting my post short because I have to go to work.