I don't know the exact pros and cons of each but I have heard that systems based makes it a lot easier to learn esp. for the boards. Also, most if not all schools in TX have converted to systems based learning. I just interviewed as WVSOM and they had both PBL and Systems but now they got rid of PBL. So I guess it's a new trend or something? I am not choosing a school soley based on this curriculum but it is one of the biggest determining factors.