Legit quality cinnamon is deeply earthy, woodsy, spicy, and naturally sweet, with fragrant oils reminiscent of a just-peeled orange. It makes a powerful upgrade to pie filling, cookies, and hot chocolate, and you can use far less of it to bring noticeably sweet and spicy flavors up to your nose.To simplify things a bit, there are two cinnamon varieties to look out for: Cinnamomum cassia, a Chinese version that has the brusque, robustly spicy flavor you taste in Big Red chewing gum and Hot Tamales candy, and Cinnamomum verum, a tree native to Sri Lanka but now also grown elsewhere, that's more gentle, vanilla- and orange-forward, and reedy in character. Cassia takes especially well to Chinese cooking and American baking recipes where you want cinnamon to punch you in the gut; C. verum is more of a team player, particularly where other sweet spices are concerned. While Mexican groceries tend to sell decent quality C. verum (most American groceries sell cassia), the best grades of both varieties are usually sold online. For a real special treat, pick up La Boite's smoked C. verum, which is nothing short of a pastry gamechanger.

Source: http://www.seriouseats.com/2015/06/expensive-spices-worth-the-splurge.html