I went to Waterloo as well and absolutely loved the 4-month co-op terms and would have hated being limited to a single 18-month term with a single company. You get to try a little bit of everything. I did big companies (BNR, NT in Toronto), a smaller Toronto startup and mid-size (Novatel in Calgary) and after freezing my a in Alberta for a winter term went to southern Brazil for my next two terms.