PVP is team based and that's exactly the reason why there is no "best class" for PVP.
You need every class to be succesful. If you only got ranged classes, you won't win anything. If you play melee, you have to play smart and don't charge into the 5 enemies finishing of 1 guy from your team.
As a marauder, I can really pick my targets and I prefer the stupid guys chilling in the back, thinking they can free cast on anything. If you jump into their face and circle them while shoving your lightsaber up their arse, they usually don't know what to do. I really enjoy the Marauder and I was nearly always top 3 in damage and objectives even tho everyone says, that the class is gimped.