Tenderloin is considered the tenderest cut of beef, with a delicate flavor and buttery texture. It's leaner than other cuts and doesn't have much marbling, so it needs to be cooked carefully to avoid becoming tough.  Filet mignon, on the other hand, is cut from the tenderloin and is a small, round steak that's even more tender than regular tenderloin. It has a slightly bolder flavor and takes well to marinating or seasoning.  If you want a very tender piece of beef with a mild flavor, tenderloin is the way to go. If you're looking for a steak that takes well to marinating and seasoning, filet mignon is the better choice. Ultimately, it comes down to personal preference. Both are delicious!