I have a heat pump tumble dryer, which is brilliant and cheap to run. My washing machine is usually set to a 1600rpm final spin, and I am always totally astonished as to how much water comes out off my washing in the dryer. I always empty that and the fluff after each use.
In my old house, I only used a tumble dryer very occasionally, and in good weather always put washing outside. Must say, the question about the fluff did cross my mind recently - wondering why I never saw this with my whirlygig dried washing.
However, in a flat this dryer really has earned its purchase price.