what are the differences between the education systems (university)
Check out the ' How difficult is it to get into Wrocław University of Technology' thread, if you haven't already looked, there are relevant bits of info in there regarding quality of courses etc. To get into a Polish Uni, you need to pass the Matura, which is on a par with the International Baccalaureate. Not sure what the US equivalent of this is, or if a Polish University will recognize the US equivalent, you would have to check. Bear in mind though that if you are accepted, and complete your degree in Poland, as a non-native speaker, you will be at a disadvantage when it comes to employment. However you'll have plenty of time to learn :). You also need to consider that if you return to the US for employment, how well regarded would a degree from a Polish University be? Just couple things to think about!
What about the differences in food?
On the plus side for you, Poland does have Mcdonalds, KFC, Pizza Hut etc.......but you'll be a poor student and watching your pennies!
You will probably find Polish food very bland in comparison to food in US. Depends what you eat. Polish food is heavy on meat/potatoes/cabbage.
Don't expect to find a lot of spicy food on offer. Typical dishes: Kotlet Schabowy, Gołąbki, Pierogi, Bigos. Poles are also fond of soups, Barszcz, Rosół etc. Polish cakes and desserts are to die for!
Good luck if you decide to go for it, sure it'll be a great experience for you :)