to be honest I'd never touch a fillet or a sirloin give me a ribeye or a thick rump any day more flavour ..
The T-bone I did on the BBQ at the weekend says otherwise It's the quality of the meat, what the cow was fed on and how well aged it is that makes the real difference IMO. A fillet from the right cow/butcher would have better flavour than a bad ribeye or rump. Of course a good ribeye or rump can be epic too.