Professional hair brushes are good, but I have never had a problem finding a good hair brush at a department store's health and beauty section. My biggest criteria is how easy the brush is to keep clean. I use a lot of hair products, and the best hair brush for me is one that I can take apart and clean. I will sometimes soak my hair brush in a solution of baking soda and water to break up the residue on bristles.
Speaking of bristles, I also find a natural bristle hair brush is easier to work with than one with plastic bristles. Sometimes I can feel the plastic bristles scraping against my scalp and it's not pleasant. Those little protective beads can also work loose over time. I also carry a portable hair brush that folds on itself, since combs really don't work well on my hair.