so just to get it straight...PBL is only used to reinforce things taught in lectures? Right? I mean we wont be teaching each other fresh topics etc?
Yes, its never completely new, just a clinical extension of lecture topics.

PBL's are good because they are interactive. You progress through a clinical scenario and try to emulate the 'thought processes of a clinician'.

Poorly informed tutors or badly prepared students can make the exercise less useful, unless you have some super students in your group that take it up up on themselves to teach the group everything (they do exist). Some tutors (rare) are not too nice to students when they don't know something. I think tutors should always be ever considerate of different students level of knowledge.