1. Every year the government gives you $400 (or 20% of you investment, which is less).
2. The interest of that investment is tax-free (in fact, when your child uses these money, s/he will pay the tax, but since s/he has no other income, the tax rate is fare low)
And, it has some restrictions, for example,
1. No matter how much you buy, you can get at most 400 a year
2. Your kid must study at post-secondary school to be able to get these benefit. The restrictions are not the same on this, so check with your institution.
3. If you quit, you will lose a lot. Also, ask the salesman and be aware before you enroll.
Personally, I only want to get the 400 bonus, and don't care much about the interest. Select one of the largest institution.