We love our DnFs. We only have 3 atm as she has just outgrown the 2 smalls we had. Best fitting fitted we own at the moment and we think they are great absorbency wise, if only they did a higher rise NN - id be in heaven! x
We've got 5, because they stand up to my heavy wetter. I fold most of the boosters in two, so that there are something like 10 layers of fabric in Iris' wetzone excluding the actual nappy (I leave the top booster laid flat, to hold everything else in place). I think they're quite adaptable for a heavy wetter. And they fit like a dream, too.