This is, hands down, the best toothpaste I have ever owned! It gives results as soon as the first use. It comes in a funky blue color, but has a nice "Happy Mint" flavor. It is also backed by Allure magazine. It you are looking to start whitening fast, then I highly suggest you try Luster first!
I've never been able to find a toothpaste that instantly whitens, but this does just that. It works so well. It has instant and lasting effects. I use it a few times a week and see my teeth are noticeably whiter!