Tyres now come with EU performance guides (easily seen on blackcircles), and therefore you can tell at a glace if the Michelins are actually more fuel efficient than the budget brand, or if the Continentals do have more grip than the Japanese equivalent. Takes all the guessing out of the equation, and cuts through the marketing rubbish. Oh, and never listen to empirical tales. If you replace a badly worn tyre with a new one, of course it is going to be much grippier, better ride, etc. Even if you replace a branded worn with a budget new one. And the drop-off in performance is so gradual I'm not convinced anyone can give a realistic comparison between their last set of tyres and the current ones.
Also, if you drive enthusiastically, some will advise putting newer tyres on the back regardless of where the power goes, as loosing grip at the back is much more difficult to catch on a front wheel drive than loosing it at the front. And for a rear wheel drive, that's where you want the grip anyway.