Vantaggi
RIM is a great place to work for co-op, you can learn so much and by the end of your 4 months you are still learning. I'd highly recommend doing at least two co-op terms for the same position since you will probably learn way more your 2nd time around. Plus there are bonuses to your pay should you decide to return. Not to mention a free BlackBerry you get to keep during your school term =) but it's only Data and not voice... other than that this place is a great place for co-op. Good pay. Good people (mostly). Good company.
Svantaggi
I would say the downsides are the same as a pro side. "BlackBerrys"... they are really an amazing piece of technology but at the same time you get bound to them. RIM is very smart for giving all their employees free BlackBerrys. You get bound to it and you constantly check your BlackBerry even though you are off work. Free phone would be a pretty sweet deal but you really do end up as a "CrackBerry Addict"... Another downside would be the same as all other companies out there. Some teams are just plan disorganized and should really be trained to have better mangement.