Those days are gone. " big differences " ? ...... I don,t think so.
The Hitman, how wrong can you be, In Krakow for example there is always as much as 10% difference between the good and bad Kantors.
I don't understand why people still use kantors. Taking money out of machines gives you a decent rate. Perhaps I'm just with a reasonable bank....
Why wouldn't you use Kantors, they give you the best rates at zero commission?
I even use them for large transactions, bringing cash from UK and changing at a Kantor, always gives me an even better rate than using any of the main Forex companies.