This is a comparison of 1ct ideal cut, F color, SI1 clarity pear cut diamonds (click the dollar amount to be taken directly to the diamond):

James Allen: $3280

Blue Nile: $4267

Abazias: $4776

White Flash: $4791

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.