The board from the Light Impression of old was great -- I used Bright White for all my silver gelatin work -- including the Portriga Rapid (lightly selenium toned).
But their Natural White was great for my platinums and warm carbon prints. A perfect clean-looking light cream.
Another company's "Natural White" (don't know who), is way too yellow -- closer to what I have seen as "Antique White". I should have bought a sampler before buying 10 full (32x40) sheets of 8-ply of it! As Jon mentioned, a little sickly-looking. But I have used it for some very warm images (like the salt print I recently made) and it looks fine. And I will use it to re-mat the two Watkins 16x20 prints I have -- the color will work well with old albuman prints (bad spelling!).