It's a defense over offense thing. X7's are tanky, while TIE/D's hit like a meteor. In good hands, tie/D's can be more deadly then x7's.So it seems the X7 title is popular. No love for the TIE/D?
This is truth. The neat thing about TIE/Ds is that you pack multi-ship firepower and some control into a single, fast small base that pays relatively little for PS. TIE/Ds are going to die faster, and they will be weak to things that x7s are not, but they will kill things a lot faster (which saves them some damage) and they will control things (which also saves some damage). They have more upside, but also more downside. If you don't want games going to time, take TIE/Ds.