I use a few of each for my birds, except for the tiel. Pepper freaks completely if I try putting anything that looks like a branch anywhere near his cage! So, I have a dowel perch for him, a plastic perch, and a branch that is peeled and almost straight, so he THINKS it isn't a branch.
Sage, the special needs white-eared conure, has two pieces of branch that have been sanded to be flat on the top (and smooth so they don't hurt her feet, although I have strips of rawhide wrapped around parts of them), a box made out of pine that she sleeps in (but also sits in the entrance of occasionally), and a swing with a really skinny dowel (about 1/4") that Murray made for her. She doesn't use the swing a lot, but every once in a while she perches there for a bit. It's just barely above the bottom of her cage, so if she missteps she won't really fall.
She also has old placemats in the bottom of her cage to help her walk around over the bars, otherwise her poor little legs would go right between the bars!
Abby