So when Legion was in the works, and all the theorycrafters were putting Marksmanship on a pedestal as the "raiding spec" of Legion, I obviously chose it as my first artifact weapon to pursue. I admittedly hated the rotation (not the spec), it felt super clunky to me, hated Sidewinders, hated the downtime. But in the end, I care about my dps in raids, so I stuck with it. Now, BM has pulled ahead on ST (which is mainly what I care about) and I finally gave in and started filling up my BM artifact. Now that I got my 3 golds, I am really noticing a difference in my numbers and I am liking it. The only fights in current content I use Marks for is Il'gynoth and Helya. Single target and high movement fights, BM is just superior.
9 years ago when I made my hunter, I made it because I thought it was cool to have pets, and its kind of nice to have them again. I don't think I've used a pet since Lone Wolf first came out several years ago.
So to all the people who claim BM is the "noob" spec, or "LOL 3-button rotation spec", all I can say is give it a try.
For the record, if 7.1.5 brings better changes to Marksmanship and/or it does more ST damage, I will probably go back to it. For the moment, I'm liking BM though!