You can fit an amazing amount inside. There isn't one ultimate composting technique. The best one is the one that works for you. In the fall, I put my leaves in a wire bin. During the winter here in northern Vermont, I use a bin with a snug-fitting lid.
Tumblers are good for making quick batches of compost.
I've even composted in a black plastic garbage bag. I collected a bunch of bedding hay and horse manure one spring intending to add it to my compost pile. I forgot about the bag until late summer, and when I opened it up it was crumbly and black. And that leads me to one last tip. These little known, low-tech approaches are not only easy, but have some other big benefits, too.