do not get one simply b'cos of its certified nature, i believe almost all shops selling diamonds here are certified, it simply indicate tt it is a real diamond..with comments on its shape/cut/color etc. And there are plenty of diamond certifying bodies around, some more reputable than others of cos.
a simple analogy is a 'o' level certs tt has all 'As' and one with all 'Fs'...all r certs. but not equal...think you shld hv my pt.
my take is, buy the most valuable diamond tt you can afford.
hv a reasonable budget n get e best.
No point buying a 'big' 100 pointers when it looks pale in comparision.
Remember a diamond has no real resale value and can only sparkle, so get one tt does it best!
The reason why different makes of diamonds shine the same to us is because of the amplified lighting nature of the jeweller's store.
If you switch some of those 'foreign' sources and use the ambience lighting, it should give you a fair indication of the stone tt shines better.
A reputable store with a long tradition is preferred, do not fall for those coined terms aka commercial gimmicks.
good luck for your purchase!!