To answer your questions directly. Yes PBL has 3 exams, and I guess we all "struggle" at times, but it's just as manageable as any of the other pathways. The PBL students are relaxed 85% of the year but we go into caveman mode during the week before each of our exams. PBL will give you the most free time, that's for certain. But you need to use that time properly. In PBL you assign the pages and each exam is custom made. You will not have anymore guidance than knowing the pages you assigned. You start to get a feel for the type of questions they ask depending on the textbook assigned. Our averages are from 83%-86% on our exams.
DSP has quite a few exams (think once a week/ every two weeks). They mirror LDP in anatomy and neuroanatomy (mandatory attendance), and they pretty much mirror LDP during systems (no mandatory attendence), but they just read their textbooks. DSP will have 14 non/OPP,H&P exams next semester. If you include all exams they are probably around 20-25. Because of the mandatory attendance, all of the DSP students hang out with everyone else. They seem to study together, but it's not like they are loners or anything.
I've posted this previously, but it's buried somewhere deep in this thread.