Hi Magnolia, when I was searching for mine, also found that whiteflash seems cheaper but cannot find a piece that I like. Thus went with diamondideals and nvr regretted.
The buying experience is pretty gd. Confirm the diamond with megan, when to TT the $$ to their acount. She'll acknowledge and let me know when the shippment will arrive. When it arrive, FedEx will ask me to pay the Singapore tax. Once received, they will deliver to my home. In all, it takes less than 2 weeks in my case.
Btw, I think you can request for them to send to an independent apprasial in the states. From the independent report, it may help you to decide athought I did not do it.
One word of caution; always bring the diamond to for a local apprasial to be sure that it is the correct diamond delivered. For my case, I just when for a vocal apprasial since it already comes with the AGS cert.
Cheers
JC