Sirloin, ribeye and filet mignon are different cuts of beef, and they have the following differences:

Sirloin steak: Sirloin steak is usually considered to be the most flavorful among steaks. One of the parts, it is located on the backbone of the cow. Sirloin steak is also popular because of its tender texture and delicious taste, which usually contains some fat.

Ribeye steak: Ribeye steak, also known as gazelle steak, is located on the shoulder of the cow. It is usually fatter than sirloin steak and has a richer beef flavor. Since it's meatier than sirloin steak, ribeye steak is also more expensive than sirloin steak.

File mignon: Filet mignon is located on the spine of the cow, which is one of the most tender parts of the cow. It is not as fat as ribeye and sirloin steak, but the meat is very tender and has an excellent taste. Filet mignon is typically one of the most expensive cuts of steak.

In general, these cuts of beef vary in taste, texture and price, so you can choose according to your taste and budget.