It depends, I think with 7.3 you'll see a lot more people playing with their right nut. If you look at the sims you'll see a lot of people doing well with the left nut but it's not always that simple, sometimes the right nut will outperform the left in every way if you just pay attention to positioning.
Also the right nut will help your raid much better, having said that they both have good burst if you know how to finesse them respectively.