fitteds. I wanted to do this because we only have a clothesline at the cabin, not a dryer. Cotton twill doesn't get crunchy like other fabrics can when line dried, and when made into a flat, it line dries fairly quick in comparison to a fitted diaper.
I didn't think I would like flats . . . but as it turns out I love them! Granted they aren't my favorite for containing messy poops, and that may be my fault for how I fold them - but they are a very nice one-size option. The ones I made are smaller than a traditional flat: I took one yard of cotton twill, kept it folded in half the way it comes off the bolt, and cut it in half at 18". This makes two double-sided flats out of each yard. I lay in an insert and fold the flat to the rise I need, and voila, a diaper!
Flats are also a nice option when your baby needs a more breatheable diaper. While I love fitted diapers and find them to be quite breatheable when used coverless around the house, the gussets at the legs do hold in more heat than a non-elastic flat diaper.
I'm so glad I tried flats! As the saying goes ~ you never know what you'll like unless you try it!