I made the Watermelon Salad (mostly credited to Nigella), and here is what I think. I thought it was great.
It is a perfect salad to serve at a BBQ, especially when at dusk or after dark. It is like the juiciest tomato salad; the watermelon looses its particular flavor when combined with the oil & vinegar, and just tastes like juicy tomatoes. If you can't get perfectly ripe tomatoes, this is the way to go but don't tell anyone what you did, if you can help it!!