I think it an interesting tool, and worth using, but it has major flaws. Just use it as one other factor to help you make choices, and it's probably not one of the most important. One example of its flaws is highlighted in my latest pair of hand regs.
I registered PetroRuble.com together with the popular mis-spelling PetroRouble.com. There are almost 12 million pages listed on Google for the word "rouble", but over 65 million for the correct spelling. However, Google trends shows a massive preference for "rouble" when surfers are searching. I believe that the commercial value of PetroRouble.com is higher than the correct spelling because of these search patterns. However, Estibot values the correctly spelt name at $45, and the incorrect one at $0.