There is beef and beef. If you use some of the traditional breeds, gras fed, killed at 30 months and hung well you will have a better eating experience than a grain fed lean, continental breed killed at 18 months. Supermarket buying is pot luck and you are as likely to get the one as the other.
The difference is most noticeable in the more marginal cuts, whereas the pure muscle joints like filet will not show quite as much difference. My favourite meal from our own Ruby Red Devon beef is shin. The longer you cook it the better it gets.