I found below GIA very good cut diamond much brighter in the video than the H&A EX cut diamond. Contradict with the supposed cut grade and light performance corelation. Anyone know why?
Is it worth to pay up for a better cut?
GIA VG cut:
www.jamesallen.com
GIA EX H&A diamond 1:
www.jamesallen.com
GIA EX H&A diamond 2:
www.jamesallen.com
Is it worth to pay up for a better cut?
GIA VG cut:

2.00 Carat round diamond
This 2 carat round diamond D color vvs2 clarity has Very Good proportions and a diamond grading report from GIA
GIA EX H&A diamond 1:

2.03 Carat round diamond
This True Hearts TM diamond, 2.03 carat D color vvs2 clarity has ideal proportions and a diamond grading report from GIA
GIA EX H&A diamond 2:

2.36 Carat round diamond
This True Hearts TM diamond, 2.36 carat D color if clarity has ideal proportions and a diamond grading report from GIA