There's quite a difference. A hot, boiling wort - at least for many, many minutes from the moment you stopped boiling - will still be hot enough ( it will very slowly cool down on itw own at room temperature, but that takes ages ) to extract lots of bitterness from the added hops. This results in less aroma and flavour, although a bit more than say boiling hops continously at the same temperature for 20-60 minutes.
A wort you quickly chill down to under 160F ( in the course of 15 mnutes - it depends of course on how efficient your chiller is ) and add hops to, will extract less bitterness and actually allow the hop oils and polyphenols to infuse the wort, adding more aroma and flavour to the final beer. ( provided you do not dry hop / dry hopping on its own will add more aroma to the beer )
You can easily experiment how a temperature difference affects hop aroma and flavour, by brewing 2 exact batches, one you add hops at flameout and let them steep for 30 minutes and one where you cool down the wort to 160F and then add the hops to steep for 30 minutes. Ferment with the same yeast and package the exact same way. It should provid enough experience, to either trying more of these batches or simply deciding upon which of the methods you would like to continue with.
