Loofabear, your stone is absolutely gorgeous!! I have a 3.5 carat J stone, and it occasionally will take on a yellowish hue, but that doesn't happen very often. In some light it will take on a grey-blackish tone, like in the first 2 pictures of Swanky's stone, one of the places being in the overhead lights over the counter at the jewelry store (they definitely need to change that lighting!). But 98% of the time my stone looks white and has a fire in it that's amazing. The light in my stone dances in such a beautiful way that I wouldn't trade it for the world!
When I bought my stone, we brought in other stones, including a g and an h, and the i stone I was trading in, to compare them side-by-side, and in different light, sitting on different colors. There was no discernible difference to my eye or my husband's eye. And when we asked a customer and another diamond salesman to guess which ones were the higher and lower color grades, the guesses they made were wrong. It just wasn't worth it to go up in price for the higher colors, in my opinion.
Enjoy your beautiful diamond!