The best high-quality meats (most tender and flavorful) will be prime cut, AAA or Certified Angus Beef. These will only need about an hour to cook (or 90 minutes if 2 inches/5 cm. The next best is Choice cut. I would sous vide these steaks for 2-3 hours for a tender steak. If possible, use a steak that is at least 1 1/2- 1 1/2 inches thick. This will ensure the middle stays pink.