Hii, im from the netherlands and know people who study at both universities. In terms of education, the universities are both really good and are high up in rankings, so I wouldn't say theres a big difference between the two, although there may be differences for certain courses. Then, Leiden is a much smaller city than Amsterdam. But Leiden is a student town so there are enough things to do. They both have big body of international students, but since amsterdam is bigger and has other universities, there are more international students there. In terms of finance, there is a huge house crisis in the whole country, but amsterdam is the city where its the hardest to find accommodation and where accommodation is also the most expensive. Since youre international, im assuming either university will help you with accommodation, because otherwise its kinda impossible to find unless you know the right people. Since amsterdam is the capital and touristy, things tend to be more expensive there as well but i dont think theres a very big difference in costs between either city.