Aiyah..all gimmicks la..SK have their Brilliant Rose cut, Goldheart have their Celestial cut..they all claim only they have this kind of cut..of cuz la! They modify other people's cut a bit here and there and claim it to be their own unique cut and claim that their cut will make their diamonds the brightest of all..bullsh!t..

Yes, indeed the cut of the diamond is very important to determine whether will it shine brightly or not..but if you compare, let's say, SK's Brilliant Rose and Goldheart's Celestial, I think you won't be able to tell which is brighter..
But some are rather unique..like Lee Hwa's Hearts on Fire..can really see hearts in the cut of the diamond..but again, that's with microscope..with our naked eyes, it's just another shiny diamond..
And like what mr_sotong said..diamonds ARE indeed overrated..