That's one of the main sites that locals use. The selection in Finland is pretty low in numbers, due to increasingly strict laws against prostitution. Most of those girls are foreigners, even those that claim to be Finns. If you want to have a Finnish girl, your chances are much higher if you just go out to a bar and try to chat them up. As for the working girls on that site, it's hit or miss. You might end up with someone great, or you might get someone who used fake pictures and is hideous.