Oh yeah, BMS Belay Spool was very useful. At first, I wished we had three on the two maple job yesterday, but then it didn't matter much, except I had to help chip, which I'm okay with, but not excited about.
Many times there was enough friction from the falling end rope weight to just drop the piece without anyone holding the rope, allowing the piece to drift away from the building. Worked fine for a speedline anchor on the ground as well, as you'd expect.