I'm in the minority; but BJs just aren't my favorite trigger. They can be on the wussy side and hide too much, especially with extremely active tankmates. (Maybe not a problem in a reef.) A Sargassum is a magnificent fish that doesn't bother tankmates and they usually don't bother them either. I have two Sargassums together now (in a FOWLR), wasn't sure it was a good idea, but its working so far. Sargassums are also much more "up front" and bigger beggers than BJs. One of mine can be finger fed. If the Sargassum doesn't work out, they are great sailfish bait (long story).
I don't know if this means anything, but I hang around the disease forum a lot and there seems to be too many BJs showing up with problems lately. This isn't scientific, just my observation. BTW, I really like Niger's in a reef tank. They usually aren't included in reef-safe trigger lists, but should be, IMO.