I'm finding that BM for every fight is the way to go so far. Unfortunately, I wasn't brought in for Spoils or Thok, so I cannot say. But damage alone, BM seems to be way ahead. The change to Dash with Blink Strikes and Kill Command having a 25 yard range, has made target switching for BM MUCH easier.
For normals at least, I see no reason to switch to SV right now. Heroics may change that.