Pure Numbers, BM or MM for Legion raiding?

[jmaster299 5]

I know this is a question with an answer that may change between now and when mythic raids open a month from now, but I am seeing so much conflicting information from so many different sources, I am hoping someone can give me more of a straight answer. While I personally have not played BM or MM yet in Legion, as I was not in the Beta, I am comfortable with either spec. And, based on what I've read, and experienced in the pre patch, I am enjoying BM more than I am MM.

People may feel that not having a cast time on BM makes it too easy, but I personally rather have that if I am going to have to fulfil the traditional role of a Hunter in raids. Which generally means a lot of movement and priority add switching. My main concern is making sure I am leveling my Artifact weapon for the correct spec first, as well as putting a focus on gear in terms of the best stats to be able to walk into Legion raiding as prepared as I possibly can be. It also matters so I can focus on the proper BiS items to spend EPGP on.

From what I've read, MM seems to be the better single target spec, and BM seems to be the better 2 or more target spec. But one will always have to give way to the other, it's just not possible to be able to gear up and spend Artifact power in such a way to keep both specs equal. That said, I am trying to determine which of those two specs edges out the other. I won't neglect the other spec, and I know full well that as you level up your artifact weapon, that the cost of powering up one spec will get so expensive that it becomes better to spend points in the other spec.

But for the most part there seems to be way too much fighting between the different people who do the theorycrafting and posting guides to be able to look at one and say "this guy is clearly providing the correct information I need".

[Iridar 80]

Trust Azor. If you want to deal as much damage as possible, no compromise, he's your guy. 

Icy Veins hunter guides are written by him, and he says to go MM: https://www.icy-veins.com/wow/marksmanship-hunter-pve-dps-guide