I was able to participate just once in this contest, BUT, all the good things that i have been able to go through after that are just great, i mean, sometimes we just see it as a extracurricular contest, and in some way it is, but the knowledge that we gain after participating or while coaching (like me after graduating) stays with us, and it can help us in a future.
For example, im doing an Advance Master in Artificial Intelligence in Belgium and most people say that the exams are pretty difficult here and that is completely difficult to just even finishing answering all the problems (regarding programing courses) and i just had my first PROLOG exam las friday and compared to an ACM problem that was piece of cake, the 3 problems i need it to solve where way easier than solving challenging problems in ACM.
So the BIG pros we get after learning what we learn in this extracurricular contest in KNOWLEDGE and an OPEN MIND to be able to think out of the box, and that is translated into VERY GOOD JOB OFFERS and ACADEMIC OPPORTUNITIES so my message to all of you is, enjoy the time you have to participate and prepare the most you can, and you will never regretted even if you dont win.