<p>I think the biggest problem with the quarter system is that it is very unforgiving. If you get behind in a class for <em>any</em> reason it can be a significant ding on your GPA. I liked the quarter system because you could take more classes--electives in three subjects instead of two--but I think I would have done better on a semester system a couple of times.</p>
<p>Quarter system is a more ambitious system because you can get to do more with the schedule if you choose to. That, of course, works well for more ambitious/disciplined students. My friend was able to get a comp sci and a econ degrees + 6 quarters of co-op in 4 years! Lots of people (including myself) finished with dual-degree at Northwestern.</p>