i have 5 of em.
i use the dual trim sill brushes on carbon goosenecks for maintenance cleans(soft and medium bristle)
an extreme medium bristle on my 40 ft supermax with carbon gooseneck
and 2 standard dual trim supalites(soft and medium bristle)for conny roofs and first cleans.
they are really light.the best for scrubbing glass is the standard DT SUPALITE IMO.but the sill brushes do me for most window cleaning work.i dont scratch sills either!
best wishes
dazmond