It depends on a few factors, such as your personal preference and the quality of the tea. Bagged tea leaves are often cut into fine dust, making it easier for flavors to steep into your tea; this also means that bitter tannins can come out faster. Additionally, powdered tea bags are often made of leaves that didn't pass the whole, loose leaf tea quality check. Loose tea leaves are usually still whole, so you have a little more wiggle room with temperature and brewing time. For instance, tea made with green tea leaves may not taste as bitter as tea brewed with a green tea bag. We say: taste both and see what you prefer!