This is a comparison of 2ct ideal cut, G color, VS1 clarity princess cut diamonds (click the dollar amount to be taken directly to the diamond):

James Allen: $15,070

White Flash: $18,071

Abazias: $20,117

Blue Nile: $20,129

These diamonds are independently inspected and graded by GIA/AGS, which means you can trust their quality. The quality of these diamonds is identical--the only thing that is different is the price.