This is a comparison of 1.25ct ideal cut, F color, VS2 clarity Princess cut diamonds (click the dollar amount to be taken directly to the diamond):

James Allen: $7060

Abazias: $7730

Blue Nile: $8565

Brilliant Earth: $9210

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.