Both my coops are dirt. I use straw in the small one and wood shavings and pellets in the large one, along with some DE. Gotta get over to the burn pile and gather some of those ashes.... Dirt is cooler for them in the summer than wood or vinyl would be. Just be sure it's higher than the surrounding ground, if you are building one like this, and allow for the inevitable raking out of some dirt. I probably rake the old one about every 4 months.
I've also used pelleted lime to help with odor; works as well as pine pellets (Stall-Dri) in my experience. There is a type of lime you can't use, though, and I can never remember, so I buy pelleted because I remember it's ok! Just need a few handfuls strewn around. Besides, pelleted isn't dusty.