No matter what you do, you have to learn the basic science information, which isn't inherently difficult. What makes things difficult is how your school may present the information, i.e.:
*does the school require alot of small group sessions which prevent you from studying what will actually be tested
*Do the histo or path teachers force you to know alot of stupid details related to their research, or do they teach you what you need to know for the wards and the boards
*How long does the school keep you in lecture? The longer lecture time, the less time you have to digest the info for yourself
*Are the lecture notes sufficient for studying, or do you have to read alot of books just to get what the lecture notes are saying?
There's a plethora of different things that the school could do to make the science presented more difficult than it needs to be. But overall, all schools need to prepare you for the boards, so all schools will be difficult in that respect.