hey guys!
I just want to pop in and say a few things as I'm from and currently living in Poznań.
So city-wise, I'd say Poznań is a really nice place to live in, it is cheaper than Warsaw definitely in terms of rent and stuff like that, it has a lot of activities to do, plenty of night clubs, bars etc. and I would also say it's a pretty safe city - you can rarely hear about someone being mugged or something, ofc depends on the districts you visit hahah. I have been to Warsaw a few times and Kraków once and if I were to choose a city to go to uni in, I'd choose Warsaw, but I think it might be partially because I wouldn't like to stay in my home city (and the reason why I'm planning on going abroad haha). I'd say all of these cities are big and there is no much difference in terms of noise and it's generally noisy in all of those in the city centre, but you can easily find a flat for rent in some districts a bit outside of the city centre which still have great public transport to go to the rest of the city or what's also popular you can find a place inside a closed area (no idea what's it called even in Polish haha), but my parents have a flat in such a 'closed area' next to one of the busiest streets and you can barely hear anything from outside due to many walls between you and the actual street.
Regarding med schools, unfortunately I can't help too much, but in general it is said that Warsaw is the best out of all (regardless of what the rankings say, because they depend on many different things), but if you take into account the whole university, then Jagiellonian is the best probably, it has the most traditions and is very well-respected. But tbh I would make the decision more based on the other factors because these are all really good universities.
And lastly, regarding English, I'd say in all of these cities, English is commonly spoken, at least when taking into account people younger than say 35 (and these are often people working in cafes, restaurants etc.), so I wouldn't worry about it at all.
If you have any more questions, I'd be more than happy to answer them!