I am looking to study at a international medical school
Better avoid Eastern european universities.They are not highly reputated and is likely to be suspected of having bribed for the degree.Maybe exception is the Karl university in Prague but again I do not know.Poznan has a faculty for international students,they try to attract foreign medical students,maybe they offer something better.
If I were you,I would prefer to study in Germany where there are some chances for research and the level of education is considered good.The entrance is also not very difficult and the demands inside the university reasonable.(drop rate 30% after exams in 2nd,4th year).Avoid South Europe as well,no advantage at all.