I'd say it's much worse than 1/3rd the quality. It's absolutely terrible! The data for London, where I live, is full of misspellings; at least one tube station

I'd say it's much worse than 1/3rd the quality. It's absolutely terrible! The data for London, where I live, is full of misspellings; at least one tube station is missing (Monument, in the heart of the financial district); and it fairly often seems to use an arbitrary street name as the name for an entire district. I wouldn't trust it to navigate me anywhere!