I say get both.
Either brush is a HUGE bargain. The SMF III is my current favorite brush FWIW and seems quite sturdily made although no admins or mods have deemed necessary to fire theirs with a propane torch or run over it with the Denali....(NO Joel I'm not sending it to you for testing ) although even as rough as I am on some of my brushes and razors, I can't imagine any of them ever needing to pass those tests,...it is, after all, not an implement for combat...
I'm looking forwards to trying the B&B brush as well, and it will be interesting to me to see how the two compare. I seriously doubt I'll be able to afford one in each grade or various types of handle or printing...but I'm sure there will be a comparison done at some point.
All that torture testing of the B&B brush has me wondering about a few other tests that would be interesting if one had brushes to spare, such as how well the brush bounces back after being used innocently by SWMBO or other female as an ersatz makeup brush, or perhaps dipped in paint...or (more real to me) hydraulic fluid, engine oil or jet fuel soaks onto the bristles...or SWMBO spills a bottle of hairspray on it.....
Don't know. Just some thoughts. IF my brush were run over by a car, then burned by a torch after all sorts of other stuff, I've got worse problems than which brush I selected.
Neither brush is to be missed.
John P.